ifcviewer: support linking system-packaged wgpu-native and zstd

Add a WGPU_NATIVE_USE_SYSTEM option that resolves wgpu-native via pkg-config instead of FetchContent-ing upstream's prebuilt binary release, for distros (e.g. Fedora) that ship it as a system package. Also fall back to pkg-config for zstd when the CONFIG package isn't available, and skip the wgpu-native runtime install step when the system package already owns it.
2026-08-24 13:56:50 +00:00 · 2026-08-19 22:06:43 +01:00
17 changed files with 514 additions and 892 deletions
@@ -64,7 +64,7 @@ jobs:
          max-size: 5000MB

      - name: Set up Python for connector build
-        uses: actions/setup-python@v7
+        uses: actions/setup-python@v6
        with:
          python-version: '3.12'

@@ -253,10 +253,6 @@ EM_BOOL onMouseDown(int, const EmscriptenMouseEvent* e, void* user) {
        app->nav_drag_px = 0.0f;
        app->down_x      = e->targetX;  // canvas-relative CSS px
        app->down_y      = e->targetY;
-        // Show the pivot triad for the duration of an orbit / pan drag, so
-        // it's visible what the camera turns around (matches the desktop).
-        if (kind == NavKind::Orbit || kind == NavKind::Pan)
-            app->core.setPivotIndicatorVisible(true);
    }
    return EM_TRUE;
 }
@@ -301,10 +297,6 @@ EM_BOOL onMouseUp(int, const EmscriptenMouseEvent* e, void* user) {
    const NavKind kind       = app->nav_kind;
    app->nav_active = false;
    app->nav_kind   = NavKind::None;
-    // Drag is over — hide the pivot indicator without afterglow. Only for the
-    // gesture that raised it; a stray mouseup must not cut a wheel afterglow.
-    if (was_active && (kind == NavKind::Orbit || kind == NavKind::Pan))
-        app->core.setPivotIndicatorVisible(false);

    // End a section-gizmo drag (took over the press; no pick/orbit on release).
    if (app->section_dragging) {
@@ -359,7 +351,7 @@ EM_BOOL onMouseUp(int, const EmscriptenMouseEvent* e, void* user) {
                if (id != 0) {
                    app->core.logSelectedObjectGuidWeb(id);
                } else if (!add && !remove) {
-                    EM_ASM({ if (Module.__ifcvOnSelect) Module.__ifcvOnSelect(0, '', -1, -1); });
+                    EM_ASM({ if (Module.__ifcvOnSelect) Module.__ifcvOnSelect(0, '', -1); });
                }
                app->host.requestFrame();
            });
@@ -381,9 +373,6 @@ EM_BOOL onWheel(int, const EmscriptenWheelEvent* e, void* user) {
    // In fly mode the wheel tunes move speed (Blender convention), not zoom.
    if (app->fly_mode) { app->core.flyAdjustSpeed(-float(dy) / 100.0f); return EM_TRUE; }
    app->core.dollyBy(-float(dy) / 100.0f);
-    // Pivot afterglow on wheel — visible for 600 ms so the user can see what
-    // they're zooming around without holding a drag.
-    app->core.setPivotIndicatorVisible(true, 600);
    return EM_TRUE;  // consume so the page doesn't scroll
 }

@@ -835,7 +824,6 @@ extern "C" EMSCRIPTEN_KEEPALIVE void ifcv_request_objects_c(int token) {
            first = false;
            json += "{\"objectId\":" + std::to_string(e.object_id)
                  + ",\"model\":"    + std::to_string(e.model_index)
-                  + ",\"sourceId\":" + std::to_string(e.source_id)
                  + ",\"guid\":"     + jsonString(e.guid)
                  + ",\"name\":"     + jsonString(e.name)
                  + ",\"type\":"     + jsonString(e.type) + '}';
@@ -1,99 +0,0 @@
-// This file was generated with the assistance of an AI coding tool.
-//
-// The RGB axis indicator, in both of its guises: the corner gizmo that sits
-// in the viewport's bottom-left, and the pivot triad that appears at the
-// orbit target while a navigation drag is running. Both are drawn by the
-// shared AxisIndicatorRenderer from ViewportCore, so a regression here would
-// most likely be a wiring one — the renderer never inited, the pivot gate
-// never set, the corner pass encoded before the surface resolved — none of
-// which any other test in the suite would notice.
-import { test, expect } from '@playwright/test';
-import zlib from 'node:zlib';
-
-// Decode the top-left pixel (RGB) of a PNG buffer. Row 0 pixel 0 is
-// filter-agnostic — every PNG predictor references zero neighbours there —
-// so this can skip filter handling entirely.
-function firstPixelRGB(png) {
-  let off = 8;
-  const idat = [];
-  while (off + 8 <= png.length) {
-    const len = png.readUInt32BE(off);
-    const type = png.toString('ascii', off + 4, off + 8);
-    const data = png.subarray(off + 8, off + 8 + len);
-    if (type === 'IDAT') idat.push(data);
-    else if (type === 'IEND') break;
-    off += 12 + len;
-  }
-  const raw = zlib.inflateSync(Buffer.concat(idat));
-  return [raw[1], raw[2], raw[3]];  // skip the row filter byte
-}
-
-// Is this pixel on the +Z arm? Its colour is Bonsai's decorator blue
-// (0.157, 0.565, 1.000), so blue leads red by a mile. Everything it can be
-// drawn over stays well under the threshold: the background is a near-grey
-// (32, 35, 41), the sample model is white, and even the dim x-ray pass —
-// 0.3 alpha where the arm is behind geometry — lands around (191, 222, 255).
-const isAxisBlue = ([r, , b]) => b - r > 30;
-
-// Sample 1x1 pixels straight up from (cx, cy), which is where the +Z arm
-// points at the default camera pitch. Stepping rather than picking one exact
-// pixel keeps this off the anti-aliased edges of a 2.5 px line.
-async function scanUp(page, cx, cy, from, to, step = 4) {
-  const hits = [];
-  for (let dy = from; dy <= to; dy += step) {
-    const png = await page.screenshot({
-      clip: { x: Math.round(cx), y: Math.round(cy - dy), width: 1, height: 1 },
-    });
-    hits.push(firstPixelRGB(png));
-  }
-  return hits;
-}
-
-async function boot(page) {
-  await page.goto('/IfcViewerWeb.html');
-  await page.waitForFunction(
-    () => !!(window.Module && window.Module._app_ptr), null, { timeout: 30_000 });
-  await page.waitForTimeout(1200);
-  return page.locator('#viewer-canvas').boundingBox();
-}
-
-test('corner axis gizmo draws in the bottom-left', async ({ page }) => {
-  const box = await boot(page);
-  // Gizmo box: 110 CSS px square, 10 px in from the bottom-left corner. The
-  // +Z arm runs up from its centre for ~39 px (arm 1.0 in a 1.4 half-extent
-  // ortho, over a 55 px half-box).
-  const cx = box.x + 10 + 55;
-  const cy = box.y + box.height - 10 - 55;
-  const hits = await scanUp(page, cx, cy, 10, 34);
-  expect(
-    hits.some(isAxisBlue),
-    `no +Z arm above the gizmo centre — corner axis missing (sampled ${JSON.stringify(hits)})`,
-  ).toBe(true);
-});
-
-test('pivot triad shows during an orbit drag and clears on release', async ({ page }) => {
-  const box = await boot(page);
-  // The orbit target projects to the viewport centre, and the pivot arms are
-  // 30 CSS px, so the +Z arm runs up from there.
-  const cx = box.x + box.width / 2;
-  const cy = box.y + box.height / 2;
-
-  const before = await scanUp(page, cx, cy, 8, 26);
-  expect(before.some(isAxisBlue), 'pivot visible before any drag').toBe(false);
-
-  await page.mouse.move(cx, cy);
-  await page.mouse.down();
-  await page.mouse.move(cx + 90, cy + 30, { steps: 8 });
-  await page.waitForTimeout(200);
-  const during = await scanUp(page, cx, cy, 8, 26);
-  await page.mouse.up();
-  expect(
-    during.some(isAxisBlue),
-    `no pivot triad mid-drag (sampled ${JSON.stringify(during)})`,
-  ).toBe(true);
-
-  // Released without afterglow — the indicator goes on the next frame.
-  await page.waitForTimeout(400);
-  const after = await scanUp(page, cx, cy, 8, 26);
-  expect(after.some(isAxisBlue), 'pivot triad still up after mouse release').toBe(false);
-});
@@ -1,84 +0,0 @@
-import { test, expect } from '@playwright/test';
-
-// Which file did this object come from? Every host page answers that by taking
-// the `model` index the viewer reports and looking it up in its own list of
-// models, in the order it added them — the mapping the API documents. The
-// index is only worth anything if it survives federated models finishing their
-// loads out of order, which is exactly what happens over a real network.
-//
-// The two georef fixtures carry fixed GUIDs, so an object can be attributed to
-// its file here without trusting the very index under test.
-const GUIDS = {
-  'georef-a': ['13r0IXtWf5pf18Q1EGzHXl', '22CLYZYiz8ZhbpLaYDVIu6'],
-  'georef-b': ['3DkP2KRu5AIRxhhAz$DcQH', '2ueyz_jIr2QgMKs4v0fWl2'],
-};
-
-test('model index follows add order when the first model loads last', async ({ page }) => {
-  const errors = [];
-  page.on('pageerror', (e) => errors.push('pageerror: ' + e.message));
-  await page.goto('/scripting.html');
-  await page.waitForFunction(() => !!(window.viewer && window.viewer.isLive()), null,
-    { timeout: 30_000 });
-
-  // georef-a is added first but served slowly, so every one of its range reads
-  // lands after georef-b's. Without a stable ordering the core hands out its
-  // load-order slots in completion order and the two models come back swapped.
-  const sourceIds = await page.evaluate(async () => {
-    const a = await window.viewer.addUrl('/georef-a.ifcview?delay=120', { replace: true });
-    const b = await window.viewer.addUrl('/georef-b.ifcview');
-    return [a, b];
-  });
-  expect(sourceIds[0]).toBeLessThan(sourceIds[1]);
-
-  await page.waitForFunction(() => window.viewer.modelCount() === 2, null, { timeout: 30_000 });
-
-  const objects = await page.evaluate(() => window.viewer.getObjects());
-  const rowFor = (guid) => objects.find((o) => o.guid === guid) || {};
-
-  for (const guid of GUIDS['georef-a']) {
-    expect(rowFor(guid).model, `${guid} belongs to georef-a, added first`).toBe(0);
-    expect(rowFor(guid).sourceId, `${guid} came from georef-a's source`).toBe(sourceIds[0]);
-  }
-  for (const guid of GUIDS['georef-b']) {
-    expect(rowFor(guid).model, `${guid} belongs to georef-b, added second`).toBe(1);
-    expect(rowFor(guid).sourceId, `${guid} came from georef-b's source`).toBe(sourceIds[1]);
-  }
-  expect(errors, errors.join('\n')).toEqual([]);
-});
-
-test('a pick reports the source the model was added from', async ({ page }) => {
-  const errors = [];
-  page.on('pageerror', (e) => errors.push('pageerror: ' + e.message));
-  await page.goto('/scripting.html');
-  await page.waitForFunction(() => !!(window.viewer && window.viewer.isLive()), null,
-    { timeout: 30_000 });
-
-  await page.evaluate(async () => {
-    await window.viewer.addUrl('/georef-a.ifcview?delay=120', { replace: true });
-    await window.viewer.addUrl('/georef-b.ifcview');
-  });
-  await page.waitForFunction(() => window.viewer.modelCount() === 2, null, { timeout: 30_000 });
-  // The pick payload is built from the element table, so make sure it is
-  // resident and take the same table to check the answer against.
-  const objects = await page.evaluate(() => window.viewer.getObjects());
-  await page.evaluate(() => window.viewer.viewAll());
-  await page.waitForTimeout(800);
-
-  // Whichever box the click lands on is fine — what is under test is that the
-  // pick and the object table agree about which file the object came from.
-  await page.evaluate(() => {
-    window.__pick = new Promise((resolve) => window.viewer.onSelect(resolve));
-  });
-  const box = await page.locator('#viewer-canvas').boundingBox();
-  // Web preset: RMB selects (LMB orbits).
-  await page.mouse.click(box.x + box.width / 2, box.y + box.height / 2, { button: 'right' });
-  const detail = await page.evaluate(() => window.__pick);
-
-  expect(detail.guid, 'click hit empty space').toBeTruthy();
-  const row = objects.find((o) => o.guid === detail.guid);
-  expect(row, 'picked a GUID that is not in the object table').toBeTruthy();
-  expect(detail.sourceId, 'pick and object table disagree on the source').toBe(row.sourceId);
-  expect(detail.modelIndex).toBe(row.model);
-  expect(detail.sourceId).not.toBeNull();
-  expect(errors, errors.join('\n')).toEqual([]);
-});
@@ -31,12 +31,6 @@ http.createServer(async (req, res) => {
  try {
    const url = new URL(req.url, `http://localhost:${PORT}`);
    let p = decodeURIComponent(url.pathname);
-    // ?delay=<ms> stalls every response for this URL, HEAD and Range alike.
-    // Load order across federated models is decided by whichever model's
-    // async read chain finishes first, so a test that wants a specific
-    // interleaving has to be able to make one source slower than another.
-    const delay = Number(url.searchParams.get('delay') || 0);
-    if (delay > 0) await new Promise((r) => setTimeout(r, delay));
    if (p === '/') p = '/IfcViewerWeb.html';
    const inRoot = path.join(ROOT, p);
    const inSrc  = path.join(SRC, p);
@@ -12,10 +12,8 @@
     eats pointer events so the drag keeps reaching the canvas. */
  #marquee { position: fixed; display: none; z-index: 50; pointer-events: none;
    border: 1px solid #4a9eff; background: rgba(74, 158, 255, 0.15); }
-  /* Log overlay sits bottom-left and never eats pointer events. Kept clear
-     of the corner axis gizmo, which the viewport draws in the bottom-left
-     110 CSS px (plus a 10 px margin). */
-  #status { position: fixed; bottom: 8px; left: 132px;
+  /* Log overlay sits bottom-left and never eats pointer events. */
+  #status { position: fixed; bottom: 8px; left: 12px;
    max-width: min(60vw, 680px); max-height: 28vh; overflow-y: auto;
    font-size: 11px;
    font-family: ui-monospace, "Cascadia Mono", Menlo, Consolas, monospace;
@@ -11,7 +11,7 @@
 //     await viewer.addFile(file, { replace: true });
 //     await viewer.addUrl('/model.ifcview');    // appends (federation)
 //
-//     const objects = await viewer.getObjects();  // [{objectId, guid, name, type, model, sourceId}]
+//     const objects = await viewer.getObjects();  // [{objectId, guid, name, type, model}]
 //     viewer.setSelection(['3vB2YO$MX4xv5uCqZZG05x']);
 //     viewer.setColor(objects.filter(o => o.type === 'IfcWall'), '#ff8800');
 //     viewer.setCamera({ yaw: 45, pitch: 30 });
@@ -21,14 +21,6 @@
 // The canvas element MUST have id="viewer-canvas" — the wasm side hard-codes
 // that selector for its WebGPU surface and input handlers.
 //
-// Model identity. addFile/addUrl return a source id: the handle for that model,
-// minted the moment it is registered and stable for the session. Objects come
-// back tagged with both their `sourceId` and a `model` index (the model's slot
-// in load order). Map an object to the file it came from through the source id
-// — the index is a POSITION, so it shifts down if an earlier model fails to
-// load, and a host keying its own list off it then attributes objects to the
-// wrong file.
-//
 // Object identity. Everything the scripting API takes or returns is keyed by
 // `objectId`: a u32 the renderer assigns, unique across the federation but only
 // meaningful for this session. IFC GlobalIds are the stable identity, and every
@@ -205,17 +197,15 @@
    // a remote URL (HTTP Range). load_sidecar_from_source_c(sid) streams one.
    Module.__ifcvSources = Module.__ifcvSources || [];

-    // The wasm calls this on every single-object pick; (0, '', -1, -1) means the
+    // The wasm calls this on every single-object pick; (0, '', -1) means the
    // selection was cleared. modelIndex is the picked object's model in load
-    // order (matches the modelProgress index) and sourceId the source it was
-    // added from, either null when unknown. A marquee box-select does NOT fire
-    // this (it has no single object) — use onSelectionChange for that.
-    Module.__ifcvOnSelect = function (objectId, guid, modelIndex, sourceId) {
+    // order (matches the modelProgress index), or -1. A marquee box-select does
+    // NOT fire this (it has no single object) — use onSelectionChange for that.
+    Module.__ifcvOnSelect = function (objectId, guid, modelIndex) {
      const detail = {
        objectId: objectId >>> 0,
        guid: guid || null,
        modelIndex: (typeof modelIndex === 'number' && modelIndex >= 0) ? modelIndex : null,
-        sourceId: (typeof sourceId === 'number' && sourceId >= 0) ? sourceId : null,
      };
      selectListeners.forEach(function (cb) {
        try { cb(detail); } catch (e) { console.error(e); }
@@ -289,8 +279,8 @@

      // ---- Events ----------------------------------------------------------

-      // Single-object picks (click). Fires with
-      // {objectId, guid, modelIndex, sourceId}. Returns an unsubscribe function.
+      // Single-object picks (click). Fires with {objectId, guid, modelIndex}.
+      // Returns an unsubscribe function.
      onSelect: function (cb) {
        selectListeners.push(cb);
        return function () {
@@ -431,14 +421,11 @@

      // ---- Objects ---------------------------------------------------------

-      // Every object in the scene:
-      // [{objectId, guid, name, type, model, sourceId}], where `model` is the
-      // index into the load-ordered model list (same index as modelProgress)
-      // and `sourceId` the source the model was added from — see the model
-      // identity note at the top of the file. Asynchronous — the element tables
-      // are fetched lazily per model so first paint never waits on them.
-      // Resolving this is also what lets every other call accept GlobalIds; the
-      // result is cached for that.
+      // Every object in the scene: [{objectId, guid, name, type, model}], where
+      // `model` is the index into the load-ordered model list (same index as
+      // modelProgress). Asynchronous — the element tables are fetched lazily per
+      // model so first paint never waits on them. Resolving this is also what
+      // lets every other call accept GlobalIds; the result is cached for that.
      getObjects: function () {
        const token = ++objectsToken;
        return new Promise(function (resolve) {
@@ -1,423 +0,0 @@
-/********************************************************************************
- *                                                                              *
- * This file is part of IfcOpenShell.                                           *
- *                                                                              *
- * IfcOpenShell is free software: you can redistribute it and/or modify         *
- * it under the terms of the Lesser GNU General Public License as published by  *
- * the Free Software Foundation, either version 3.0 of the License, or          *
- * (at your option) any later version.                                          *
- *                                                                              *
- * IfcOpenShell is distributed in the hope that it will be useful,              *
- * but WITHOUT ANY WARRANTY; without even the implied warranty of               *
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the                 *
- * Lesser GNU General Public License for more details.                          *
- *                                                                              *
- * You should have received a copy of the Lesser GNU General Public License     *
- * along with this program. If not, see <http://www.gnu.org/licenses/>.         *
- *                                                                              *
- ********************************************************************************/
-
-#include "AxisIndicatorRenderer.h"
-
-#include <algorithm>
-#include <cmath>
-#include <cstring>
-#include <string>
-
-#include "CameraMath.h"
-
-namespace {
-
-constexpr uint32_t kAxisUniformSlot = 256;  // dynamic-offset slot stride
-constexpr uint32_t kAxisVertexCount = 18;   // 3 arms x 2 triangles x 3 verts
-
-// Uniform slots in the shared buffer.
-constexpr uint32_t kSlotCorner    = 0;
-constexpr uint32_t kSlotPivot     = 1;
-constexpr uint32_t kSlotPivotXray = 2;
-
-WGPUStringView svFromCStr(const char* s) {
-    WGPUStringView v;
-    v.data   = s;
-    v.length = s ? std::strlen(s) : 0;
-    return v;
-}
-
-// Thick-line rendering helper (shared shape with the other overlays) + the
-// axis vertex shader. Each arm is expanded to a screen-space-thick,
-// anti-aliased quad.
-static const std::string AXIS_WGSL = std::string(R"WGSL(
-struct VsOut {
-    @builtin(position) clip_pos: vec4<f32>,
-    @location(0) color:  vec4<f32>,
-    @location(1) side_t: f32,
-};
-
-fn thick_line_clip(p_start: vec4<f32>, p_end: vec4<f32>,
-                   t: f32, side: f32,
-                   viewport_size: vec2<f32>,
-                   line_width_px: f32) -> vec4<f32> {
-    let p_here = mix(p_start, p_end, t);
-    let s_start = (p_start.xy / p_start.w) * viewport_size * 0.5;
-    let s_end   = (p_end.xy   / p_end.w  ) * viewport_size * 0.5;
-    let dir  = normalize(s_end - s_start);
-    let perp = vec2<f32>(-dir.y, dir.x);
-    let off_pixels = perp * (line_width_px * 0.5) * side;
-    let off_ndc    = off_pixels * 2.0 / viewport_size;
-    return vec4<f32>(p_here.xy + off_ndc * p_here.w, p_here.zw);
-}
-
-@fragment
-fn fs_main(in: VsOut) -> @location(0) vec4<f32> {
-    let d  = abs(in.side_t);
-    let aa = fwidth(in.side_t);
-    let coverage = 1.0 - smoothstep(1.0 - aa, 1.0, d);
-    return vec4<f32>(in.color.xyz, in.color.w * coverage);
-}
-
-struct AxisUniforms {
-    mvp:           mat4x4<f32>,
-    origin:        vec3<f32>,
-    arm:           f32,
-    alpha:         f32,
-    line_width_px: f32,
-    viewport_size: vec2<f32>,
-};
-
-@group(0) @binding(0) var<uniform> u: AxisUniforms;
-
-@vertex
-fn vs_main(@location(0) start: vec3<f32>,
-           @location(1) end:   vec3<f32>,
-           @location(2) col:   vec3<f32>,
-           @location(3) t:     f32,
-           @location(4) side:  f32) -> VsOut {
-    let p_start = u.mvp * vec4<f32>(u.origin + start * u.arm, 1.0);
-    let p_end   = u.mvp * vec4<f32>(u.origin + end   * u.arm, 1.0);
-    var out: VsOut;
-    out.clip_pos = thick_line_clip(p_start, p_end, t, side,
-                                    u.viewport_size, u.line_width_px);
-    out.color  = vec4<f32>(col, u.alpha);
-    out.side_t = side;
-    return out;
-}
-)WGSL");
-
-// Pack the axis uniform's 256-byte slot. Layout matches WGSL AxisUniforms:
-// mat4 + vec3 + f32 + f32 + f32 + vec2 = 96 B used, padded to 256.
-void packAxisUniform(uint8_t* dst,
-                     const Eigen::Matrix4f& mvp, const Eigen::Vector3f& origin,
-                     float arm, float alpha, float line_width_px,
-                     float viewport_w, float viewport_h) {
-    std::memset(dst, 0, kAxisUniformSlot);
-    std::memcpy(dst, mvp.data(), 16 * sizeof(float));
-    float ox = origin.x(), oy = origin.y(), oz = origin.z();
-    std::memcpy(dst + 64, &ox, sizeof(float));
-    std::memcpy(dst + 68, &oy, sizeof(float));
-    std::memcpy(dst + 72, &oz, sizeof(float));
-    std::memcpy(dst + 76, &arm,           sizeof(float));
-    std::memcpy(dst + 80, &alpha,         sizeof(float));
-    std::memcpy(dst + 84, &line_width_px, sizeof(float));
-    std::memcpy(dst + 88, &viewport_w,    sizeof(float));
-    std::memcpy(dst + 92, &viewport_h,    sizeof(float));
-}
-
-}  // namespace
-
-AxisIndicatorRenderer::~AxisIndicatorRenderer() { destroy(); }
-
-bool AxisIndicatorRenderer::init(WGPUDevice device, WGPUQueue queue,
-                                 WGPUTextureFormat color_format, int sample_count) {
-    device_ = device;
-    queue_  = queue;
-    if (!device_ || !queue_) return false;
-
-    // Bonsai decorator palette (src/bonsai/bonsai/bim/ui.py:593+):
-    //   decorator_color_error    = (1.000, 0.200, 0.322) — red    → +X
-    //   decorator_color_selected = (0.545, 0.863, 0.000) — green  → +Y
-    //   decorator_color_special  = (0.157, 0.565, 1.000) — blue   → +Z
-    // Same palette is reused for the section gizmo + marquee so all overlay
-    // colours come from one canonical source.
-    static const float axis_verts[] = {
-        //  start         end           color (RGB — Bonsai decorators)  t    side
-        // ---- +X red ----
-         0,0,0,         1,0,0,        1.000f, 0.200f, 0.322f,  0.f,  -1.f,
-         0,0,0,         1,0,0,        1.000f, 0.200f, 0.322f,  0.f,  +1.f,
-         0,0,0,         1,0,0,        1.000f, 0.200f, 0.322f,  1.f,  -1.f,
-         0,0,0,         1,0,0,        1.000f, 0.200f, 0.322f,  1.f,  -1.f,
-         0,0,0,         1,0,0,        1.000f, 0.200f, 0.322f,  0.f,  +1.f,
-         0,0,0,         1,0,0,        1.000f, 0.200f, 0.322f,  1.f,  +1.f,
-        // ---- +Y green ----
-         0,0,0,         0,1,0,        0.545f, 0.863f, 0.000f,  0.f,  -1.f,
-         0,0,0,         0,1,0,        0.545f, 0.863f, 0.000f,  0.f,  +1.f,
-         0,0,0,         0,1,0,        0.545f, 0.863f, 0.000f,  1.f,  -1.f,
-         0,0,0,         0,1,0,        0.545f, 0.863f, 0.000f,  1.f,  -1.f,
-         0,0,0,         0,1,0,        0.545f, 0.863f, 0.000f,  0.f,  +1.f,
-         0,0,0,         0,1,0,        0.545f, 0.863f, 0.000f,  1.f,  +1.f,
-        // ---- +Z blue ----
-         0,0,0,         0,0,1,        0.157f, 0.565f, 1.000f,  0.f,  -1.f,
-         0,0,0,         0,0,1,        0.157f, 0.565f, 1.000f,  0.f,  +1.f,
-         0,0,0,         0,0,1,        0.157f, 0.565f, 1.000f,  1.f,  -1.f,
-         0,0,0,         0,0,1,        0.157f, 0.565f, 1.000f,  1.f,  -1.f,
-         0,0,0,         0,0,1,        0.157f, 0.565f, 1.000f,  0.f,  +1.f,
-         0,0,0,         0,0,1,        0.157f, 0.565f, 1.000f,  1.f,  +1.f,
-    };
-
-    WGPUBufferDescriptor vb = {};
-    vb.usage = WGPUBufferUsage_Vertex | WGPUBufferUsage_CopyDst;
-    vb.size  = sizeof(axis_verts);
-    vb.label = svFromCStr("ifcviewer-wgpu.axis_vbo");
-    vertex_buffer_ = wgpuDeviceCreateBuffer(device_, &vb);
-    wgpuQueueWriteBuffer(queue_, vertex_buffer_, 0, axis_verts, sizeof(axis_verts));
-
-    WGPUBufferDescriptor ub = {};
-    ub.usage = WGPUBufferUsage_Uniform | WGPUBufferUsage_CopyDst;
-    ub.size  = 3u * kAxisUniformSlot;
-    ub.label = svFromCStr("ifcviewer-wgpu.axis_uniforms");
-    uniform_buffer_ = wgpuDeviceCreateBuffer(device_, &ub);
-
-    WGPUBindGroupLayoutEntry ble = {};
-    ble.binding                 = 0;
-    ble.visibility              = WGPUShaderStage_Vertex | WGPUShaderStage_Fragment;
-    ble.buffer.type             = WGPUBufferBindingType_Uniform;
-    ble.buffer.hasDynamicOffset = 1;
-    ble.buffer.minBindingSize   = 96;
-    WGPUBindGroupLayoutDescriptor bgl_desc = {};
-    bgl_desc.entryCount = 1;
-    bgl_desc.entries    = &ble;
-    bgl_desc.label      = svFromCStr("ifcviewer-wgpu.axis_bgl");
-    bgl_ = wgpuDeviceCreateBindGroupLayout(device_, &bgl_desc);
-
-    WGPUPipelineLayoutDescriptor pl_desc = {};
-    pl_desc.bindGroupLayoutCount = 1;
-    pl_desc.bindGroupLayouts     = &bgl_;
-    pl_desc.label                = svFromCStr("ifcviewer-wgpu.axis_pipeline_layout");
-    layout_ = wgpuDeviceCreatePipelineLayout(device_, &pl_desc);
-
-    WGPUBindGroupEntry bge = {};
-    bge.binding = 0;
-    bge.buffer  = uniform_buffer_;
-    bge.offset  = 0;
-    bge.size    = kAxisUniformSlot;
-    WGPUBindGroupDescriptor bg_desc = {};
-    bg_desc.layout     = bgl_;
-    bg_desc.entryCount = 1;
-    bg_desc.entries    = &bge;
-    bg_desc.label      = svFromCStr("ifcviewer-wgpu.axis_bind_group");
-    bind_group_ = wgpuDeviceCreateBindGroup(device_, &bg_desc);
-
-    WGPUShaderSourceWGSL wgsl = {};
-    wgsl.chain.sType = WGPUSType_ShaderSourceWGSL;
-    wgsl.code        = svFromCStr(AXIS_WGSL.c_str());
-    WGPUShaderModuleDescriptor sm_desc = {};
-    sm_desc.nextInChain = &wgsl.chain;
-    sm_desc.label       = svFromCStr("ifcviewer-wgpu.axis_wgsl");
-    shader_ = wgpuDeviceCreateShaderModule(device_, &sm_desc);
-
-    // Vertex layout: start vec3, end vec3, col vec3, t f32, side f32.
-    WGPUVertexAttribute attribs[5] = {};
-    attribs[0].format = WGPUVertexFormat_Float32x3; attribs[0].offset = 0;  attribs[0].shaderLocation = 0;
-    attribs[1].format = WGPUVertexFormat_Float32x3; attribs[1].offset = 12; attribs[1].shaderLocation = 1;
-    attribs[2].format = WGPUVertexFormat_Float32x3; attribs[2].offset = 24; attribs[2].shaderLocation = 2;
-    attribs[3].format = WGPUVertexFormat_Float32;   attribs[3].offset = 36; attribs[3].shaderLocation = 3;
-    attribs[4].format = WGPUVertexFormat_Float32;   attribs[4].offset = 40; attribs[4].shaderLocation = 4;
-    WGPUVertexBufferLayout vbl = {};
-    vbl.arrayStride    = 44;
-    vbl.stepMode       = WGPUVertexStepMode_Vertex;
-    vbl.attributeCount = 5;
-    vbl.attributes     = attribs;
-
-    WGPUBlendState blend = {};
-    blend.color.srcFactor = WGPUBlendFactor_SrcAlpha;
-    blend.color.dstFactor = WGPUBlendFactor_OneMinusSrcAlpha;
-    blend.color.operation = WGPUBlendOperation_Add;
-    blend.alpha.srcFactor = WGPUBlendFactor_One;
-    blend.alpha.dstFactor = WGPUBlendFactor_OneMinusSrcAlpha;
-    blend.alpha.operation = WGPUBlendOperation_Add;
-
-    // Pivot: inside the main MSAA pass, depth-tested against the scene but
-    // never writing depth. Two passes — LessEqual for the visible part,
-    // GreaterEqual for the dim x-ray showing through geometry.
-    auto build_pivot = [&](WGPUCompareFunction cmp, const char* label,
-                           WGPURenderPipeline& out) {
-        WGPUColorTargetState ct = {};
-        ct.format    = color_format;
-        ct.blend     = &blend;
-        ct.writeMask = WGPUColorWriteMask_All;
-
-        WGPUFragmentState frag = {};
-        frag.module      = shader_;
-        frag.entryPoint  = svFromCStr("fs_main");
-        frag.targetCount = 1;
-        frag.targets     = &ct;
-
-        WGPUDepthStencilState depth = {};
-        depth.format               = WGPUTextureFormat_Depth32Float;
-        depth.depthWriteEnabled    = WGPUOptionalBool_False;
-        depth.depthCompare         = cmp;
-        depth.stencilFront.compare = WGPUCompareFunction_Always;
-        depth.stencilBack.compare  = WGPUCompareFunction_Always;
-
-        WGPURenderPipelineDescriptor rp = {};
-        rp.layout              = layout_;
-        rp.label               = svFromCStr(label);
-        rp.vertex.module       = shader_;
-        rp.vertex.entryPoint   = svFromCStr("vs_main");
-        rp.vertex.bufferCount  = 1;
-        rp.vertex.buffers      = &vbl;
-        rp.fragment            = &frag;
-        rp.depthStencil        = &depth;
-        rp.primitive.topology  = WGPUPrimitiveTopology_TriangleList;
-        rp.primitive.cullMode  = WGPUCullMode_None;
-        rp.multisample.count   = uint32_t(sample_count);
-        rp.multisample.mask    = 0xFFFFFFFFu;
-        out = wgpuDeviceCreateRenderPipeline(device_, &rp);
-    };
-    build_pivot(WGPUCompareFunction_LessEqual,
-                "ifcviewer-wgpu.axis_pivot_pipeline", pivot_pipeline_);
-    build_pivot(WGPUCompareFunction_GreaterEqual,
-                "ifcviewer-wgpu.axis_pivot_xray_pipeline", pivot_xray_pipeline_);
-
-    // Corner: resolved surface, no depth, sampleCount=1.
-    {
-        WGPUColorTargetState ct = {};
-        ct.format    = color_format;
-        ct.blend     = &blend;
-        ct.writeMask = WGPUColorWriteMask_All;
-
-        WGPUFragmentState frag = {};
-        frag.module      = shader_;
-        frag.entryPoint  = svFromCStr("fs_main");
-        frag.targetCount = 1;
-        frag.targets     = &ct;
-
-        WGPURenderPipelineDescriptor rp = {};
-        rp.layout              = layout_;
-        rp.label               = svFromCStr("ifcviewer-wgpu.axis_corner_pipeline");
-        rp.vertex.module       = shader_;
-        rp.vertex.entryPoint   = svFromCStr("vs_main");
-        rp.vertex.bufferCount  = 1;
-        rp.vertex.buffers      = &vbl;
-        rp.fragment            = &frag;
-        rp.primitive.topology  = WGPUPrimitiveTopology_TriangleList;
-        rp.primitive.cullMode  = WGPUCullMode_None;
-        rp.multisample.count   = 1;
-        rp.multisample.mask    = 0xFFFFFFFFu;
-        corner_pipeline_ = wgpuDeviceCreateRenderPipeline(device_, &rp);
-    }
-
-    return pivot_pipeline_ && pivot_xray_pipeline_ && corner_pipeline_;
-}
-
-void AxisIndicatorRenderer::encodePivot(WGPURenderPassEncoder pass,
-                                        const OverlayFrame& f, bool visible) {
-    if (!visible || !pivot_pipeline_ || !pivot_xray_pipeline_) return;
-    if (f.viewport_h_px <= 0) return;
-
-    // Arm length = 30 logical px projected into world at the pivot's distance.
-    const float fovy_rad        = f.camera_fov_y_deg * kPiF / 180.0f;
-    const float world_per_pixel = f.camera_distance * std::tan(fovy_rad * 0.5f)
-                                  * 2.0f / float(f.viewport_h_px);
-    const float arm_pixels = 30.0f * float(f.device_pixel_ratio);
-    const float arm_world  = arm_pixels * world_per_pixel;
-
-    const float dpr    = float(f.device_pixel_ratio);
-    const float line_w = 2.5f * dpr;
-    const float vw     = float(f.viewport_w_px);
-    const float vh     = float(f.viewport_h_px);
-
-    uint8_t slot_visible[kAxisUniformSlot];
-    uint8_t slot_xray[kAxisUniformSlot];
-    packAxisUniform(slot_visible, f.view_proj, f.camera_target, arm_world,
-                    1.00f, line_w, vw, vh);
-    packAxisUniform(slot_xray,    f.view_proj, f.camera_target, arm_world,
-                    0.30f, line_w, vw, vh);
-    const uint32_t visible_off = kSlotPivot     * kAxisUniformSlot;
-    const uint32_t xray_off    = kSlotPivotXray * kAxisUniformSlot;
-    wgpuQueueWriteBuffer(queue_, uniform_buffer_, visible_off,
-                         slot_visible, sizeof(slot_visible));
-    wgpuQueueWriteBuffer(queue_, uniform_buffer_, xray_off,
-                         slot_xray, sizeof(slot_xray));
-
-    wgpuRenderPassEncoderSetVertexBuffer(pass, 0, vertex_buffer_, 0, WGPU_WHOLE_SIZE);
-    wgpuRenderPassEncoderSetPipeline(pass, pivot_xray_pipeline_);
-    wgpuRenderPassEncoderSetBindGroup(pass, 0, bind_group_, 1, &xray_off);
-    wgpuRenderPassEncoderDraw(pass, kAxisVertexCount, 1, 0, 0);
-    wgpuRenderPassEncoderSetPipeline(pass, pivot_pipeline_);
-    wgpuRenderPassEncoderSetBindGroup(pass, 0, bind_group_, 1, &visible_off);
-    wgpuRenderPassEncoderDraw(pass, kAxisVertexCount, 1, 0, 0);
-}
-
-void AxisIndicatorRenderer::encodeCornerAxis(WGPUCommandEncoder enc,
-                                             WGPUTextureView surface_view,
-                                             const OverlayFrame& f) {
-    if (!corner_pipeline_ || !surface_view) return;
-    const int dpr = std::max(1, f.device_pixel_ratio);
-    const uint32_t gizmo_size = uint32_t(110 * dpr);
-    const uint32_t margin     = uint32_t(10 * dpr);
-    if (gizmo_size == 0 || f.viewport_w_px <= 0 || f.viewport_h_px <= 0) return;
-    // Bottom-left in WebGPU framebuffer space (y down).
-    const uint32_t fb_h = uint32_t(f.viewport_h_px);
-    if (gizmo_size + margin > fb_h) return;
-    const uint32_t y = fb_h - margin - gizmo_size;
-
-    // Independent ortho projection from the camera's direction. Near the
-    // poles the up axis collapses against the look direction, so swap to
-    // Y-up there — mirrors buildViewProj's identical fix on the viewport.
-    const float yaw_rad   = f.camera_yaw_deg   * kPiF / 180.0f;
-    const float pitch_rad = f.camera_pitch_deg * kPiF / 180.0f;
-    const Eigen::Vector3f eye_dir(std::cos(pitch_rad) * std::cos(yaw_rad),
-                                  std::cos(pitch_rad) * std::sin(yaw_rad),
-                                  std::sin(pitch_rad));
-    const Eigen::Vector3f world_up = (std::abs(f.camera_pitch_deg) >= 89.0f)
-                                   ? Eigen::Vector3f(0.0f, 1.0f, 0.0f)
-                                   : Eigen::Vector3f(0.0f, 0.0f, 1.0f);
-    const Eigen::Matrix4f gv = lookAtRH(eye_dir * 3.0f, Eigen::Vector3f::Zero(), world_up);
-    const Eigen::Matrix4f gp = orthoGL(-1.4f, 1.4f, -1.4f, 1.4f, 0.1f, 10.0f);
-    Eigen::Matrix4f z_remap = Eigen::Matrix4f::Identity();
-    z_remap(2, 2) = 0.5f;
-    z_remap(2, 3) = 0.5f;
-    const Eigen::Matrix4f mvp = z_remap * gp * gv;
-
-    uint8_t slot[kAxisUniformSlot];
-    const float line_w = 2.5f * float(dpr);
-    packAxisUniform(slot, mvp, Eigen::Vector3f(0, 0, 0), 1.0f, 1.0f, line_w,
-                    float(gizmo_size), float(gizmo_size));
-    const uint32_t slot_offset = kSlotCorner * kAxisUniformSlot;
-    wgpuQueueWriteBuffer(queue_, uniform_buffer_, slot_offset, slot, sizeof(slot));
-
-    WGPURenderPassColorAttachment color = {};
-    color.view       = surface_view;
-    color.loadOp     = WGPULoadOp_Load;
-    color.storeOp    = WGPUStoreOp_Store;
-    color.clearValue = { 0.0, 0.0, 0.0, 1.0 };
-    color.depthSlice = WGPU_DEPTH_SLICE_UNDEFINED;
-
-    WGPURenderPassDescriptor pass_desc = {};
-    pass_desc.colorAttachmentCount = 1;
-    pass_desc.colorAttachments     = &color;
-    pass_desc.label                = svFromCStr("ifcviewer-wgpu.corner_axis_pass");
-
-    WGPURenderPassEncoder pass = wgpuCommandEncoderBeginRenderPass(enc, &pass_desc);
-    wgpuRenderPassEncoderSetViewport(pass, float(margin), float(y),
-                                     float(gizmo_size), float(gizmo_size),
-                                     0.0f, 1.0f);
-    wgpuRenderPassEncoderSetPipeline(pass, corner_pipeline_);
-    wgpuRenderPassEncoderSetVertexBuffer(pass, 0, vertex_buffer_, 0, WGPU_WHOLE_SIZE);
-    wgpuRenderPassEncoderSetBindGroup(pass, 0, bind_group_, 1, &slot_offset);
-    wgpuRenderPassEncoderDraw(pass, kAxisVertexCount, 1, 0, 0);
-    wgpuRenderPassEncoderEnd(pass);
-    wgpuRenderPassEncoderRelease(pass);
-}
-
-void AxisIndicatorRenderer::destroy() {
-    if (pivot_pipeline_)      { wgpuRenderPipelineRelease(pivot_pipeline_);      pivot_pipeline_ = nullptr; }
-    if (pivot_xray_pipeline_) { wgpuRenderPipelineRelease(pivot_xray_pipeline_); pivot_xray_pipeline_ = nullptr; }
-    if (corner_pipeline_)     { wgpuRenderPipelineRelease(corner_pipeline_);     corner_pipeline_ = nullptr; }
-    if (layout_)              { wgpuPipelineLayoutRelease(layout_);              layout_ = nullptr; }
-    if (bgl_)                 { wgpuBindGroupLayoutRelease(bgl_);                bgl_ = nullptr; }
-    if (bind_group_)          { wgpuBindGroupRelease(bind_group_);               bind_group_ = nullptr; }
-    if (vertex_buffer_)       { wgpuBufferRelease(vertex_buffer_);               vertex_buffer_ = nullptr; }
-    if (uniform_buffer_)      { wgpuBufferRelease(uniform_buffer_);              uniform_buffer_ = nullptr; }
-    if (shader_)              { wgpuShaderModuleRelease(shader_);                shader_ = nullptr; }
-}
@@ -1,84 +0,0 @@
-/********************************************************************************
- *                                                                              *
- * This file is part of IfcOpenShell.                                           *
- *                                                                              *
- * IfcOpenShell is free software: you can redistribute it and/or modify         *
- * it under the terms of the Lesser GNU General Public License as published by  *
- * the Free Software Foundation, either version 3.0 of the License, or          *
- * (at your option) any later version.                                          *
- *                                                                              *
- * IfcOpenShell is distributed in the hope that it will be useful,              *
- * but WITHOUT ANY WARRANTY; without even the implied warranty of               *
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the                 *
- * Lesser GNU General Public License for more details.                          *
- *                                                                              *
- * You should have received a copy of the Lesser GNU General Public License     *
- * along with this program. If not, see <http://www.gnu.org/licenses/>.         *
- *                                                                              *
- ********************************************************************************/
-
-#ifndef AXISINDICATORRENDERER_H
-#define AXISINDICATORRENDERER_H
-
-#include <webgpu/webgpu.h>
-
-#include <Eigen/Dense>
-
-#include "OverlayFrame.h"
-
-// Qt-free renderer for the RGB axis indicator, in its two guises:
-//
-//   - the corner gizmo: a fixed 110x110 px triad in the viewport's
-//     bottom-left corner, drawn on the resolved surface with its own ortho
-//     projection so only the camera's direction moves it;
-//   - the pivot indicator: the same triad drawn in world space at the orbit
-//     target while the user is navigating, depth-tested against the scene
-//     with a dim x-ray pass behind it.
-//
-// Lifted out of the Qt-coupled OverlayRenderer so BOTH the desktop and web
-// builds draw one identical indicator from a single place (ViewportCore::render
-// calls it on both) — same move SectionGizmoRenderer made.
-class AxisIndicatorRenderer {
-public:
-    AxisIndicatorRenderer() = default;
-    ~AxisIndicatorRenderer();
-    AxisIndicatorRenderer(const AxisIndicatorRenderer&)            = delete;
-    AxisIndicatorRenderer& operator=(const AxisIndicatorRenderer&) = delete;
-
-    // Create the shared triad VBO, the uniform buffer (three dynamic-offset
-    // slots: corner / pivot / pivot-xray), and the three pipelines.
-    // `color_format` is the render target's format; `sample_count` the MSAA
-    // count of the main pass the pivot draws into (the corner gizmo always
-    // targets the resolved, single-sampled surface). Returns false — and
-    // leaves the renderer inert — if pipeline creation fails.
-    bool init(WGPUDevice device, WGPUQueue queue,
-              WGPUTextureFormat color_format, int sample_count);
-    void destroy();
-    bool ready() const { return corner_pipeline_ != nullptr; }
-
-    // Orbit pivot indicator, drawn into the already-open main MSAA pass so it
-    // shares depth with the scene. `visible` is the viewport's UI gate (orbit /
-    // pan drag, wheel-zoom afterglow); when false this is a cheap no-op.
-    void encodePivot(WGPURenderPassEncoder pass, const OverlayFrame& f,
-                     bool visible);
-
-    // Corner axis gizmo (bottom-left, 110x110 px). Opens its own load-op pass
-    // on the resolved surface, so it must run after the main pass has resolved.
-    void encodeCornerAxis(WGPUCommandEncoder enc, WGPUTextureView surface_view,
-                          const OverlayFrame& f);
-
-private:
-    WGPUDevice          device_          = nullptr;
-    WGPUQueue           queue_           = nullptr;
-    WGPUShaderModule    shader_          = nullptr;
-    WGPUBindGroupLayout bgl_             = nullptr;
-    WGPUPipelineLayout  layout_          = nullptr;
-    WGPUBindGroup       bind_group_      = nullptr;
-    WGPUBuffer          vertex_buffer_   = nullptr;
-    WGPUBuffer          uniform_buffer_  = nullptr;
-    WGPURenderPipeline  pivot_pipeline_      = nullptr;
-    WGPURenderPipeline  pivot_xray_pipeline_ = nullptr;
-    WGPURenderPipeline  corner_pipeline_     = nullptr;
-};
-
-#endif  // AXISINDICATORRENDERER_H
@@ -32,13 +32,21 @@ endif()
 # everywhere a 4x4 transform shows up. Header-only, works under Emscripten.
 find_package(Eigen3 REQUIRED)

-# wgpu-native — fetched as a pre-built binary release from upstream.
-# Under Emscripten this whole block is skipped; the web build links
-# against Dawn's webgpu.h via the emdawnwebgpu port instead. The
+# wgpu-native — fetched as a pre-built binary release from upstream, or
+# taken from a system package via pkg-config when WGPU_NATIVE_USE_SYSTEM
+# is set. Under Emscripten this whole block is skipped; the web build
+# links against Dawn's webgpu.h via the emdawnwebgpu port instead. The
 # `wgpu_native` link target is created as an INTERFACE in that branch
 # (see the end of this block) so consumers' target_link_libraries lines
 # work uniformly.
-if(NOT EMSCRIPTEN)
+option(WGPU_NATIVE_USE_SYSTEM "Link against a system-packaged wgpu-native instead of FetchContent-ing upstream's prebuilt binary release" OFF)
+if(NOT EMSCRIPTEN AND WGPU_NATIVE_USE_SYSTEM)
+    find_package(PkgConfig REQUIRED)
+    pkg_check_modules(WGPU_NATIVE REQUIRED IMPORTED_TARGET wgpu-native)
+
+    add_library(wgpu_native ALIAS PkgConfig::WGPU_NATIVE)
+
+elseif(NOT EMSCRIPTEN)
 # Pin the version with WGPU_NATIVE_VERSION; bump to pull a newer release.
 set(WGPU_NATIVE_VERSION "v29.0.0.0" CACHE STRING "wgpu-native release tag")

@@ -139,7 +147,6 @@ endif()
 #
 # Keep this list explicit (no glob) — the boundary is the whole point.
 set(IFCVIEWER_CORE_SOURCES
-    AxisIndicatorRenderer.cpp
    BufferPool.cpp
    ChunkPlanner.cpp
    InstanceCompose.cpp
@@ -188,7 +195,6 @@ if(EMSCRIPTEN)
    # below which would mangle these absolute paths; added via target_sources.
 endif()
 set(IFCVIEWER_CORE_HEADERS
-    AxisIndicatorRenderer.h
    BufferPool.h
    CameraMath.h
    ChunkPlanner.h
@@ -246,8 +252,15 @@ if(EMSCRIPTEN)
    target_sources(IfcViewerCore PRIVATE ${ZSTD_DEC_SRC})
    target_include_directories(IfcViewerCore PRIVATE ${ZSTD_DEC_DIR})
 else()
-    find_package(zstd CONFIG REQUIRED)
-    target_link_libraries(IfcViewerCore PUBLIC zstd::libzstd_static)
+    find_package(zstd CONFIG QUIET)
+    if(TARGET zstd::libzstd_static)
+        target_link_libraries(IfcViewerCore PUBLIC zstd::libzstd_static)
+    else()
+        # No zstd CONFIG package on this system — fall back to pkg-config.
+        find_package(PkgConfig REQUIRED)
+        pkg_check_modules(ZSTD REQUIRED IMPORTED_TARGET libzstd)
+        target_link_libraries(IfcViewerCore PUBLIC PkgConfig::ZSTD)
+    endif()
 endif()
 install(TARGETS IfcViewerCore EXPORT ${IFCOPENSHELL_EXPORT_TARGETS})

@@ -338,7 +351,12 @@ install(FILES ${IFCVIEWER_H_FILES}
 # INSTALL_RPATH is set to @executable_path/../Frameworks — together
 # they resolve at launch without depending on macdeployqt to follow
 # non-Qt @rpath references.
-if(WIN32)
+#
+# None of this applies with WGPU_NATIVE_USE_SYSTEM: the shared library
+# already lives on the system linker path, owned by its own package.
+if(WGPU_NATIVE_USE_SYSTEM)
+    # nothing to install; system package owns libwgpu_native
+elseif(WIN32)
    install(FILES "${wgpu_native_SOURCE_DIR}/lib/${_wgpu_runtime}" DESTINATION bin)
 elseif(APPLE AND BUILD_BONSAIVIEWER)
    install(FILES "${wgpu_native_SOURCE_DIR}/lib/${_wgpu_lib}"
@@ -319,9 +319,7 @@ struct ModelGpuData {
    // (Module.__ifcvSources[id] = a picked File or a remote URL) this model's
    // chunk + element metadata reads pull from. Lets several federated models stream
    // from different files at once, mirroring the desktop per-model path.
-    // -1 when the model came from somewhere else (a path read on desktop, the
-    // embedded sample) — source id 0 is a real source, so it can't mean "none".
-    int         web_source_id = -1;
+    int         web_source_id = 0;

    // v15 element metadata (web, on-demand). The IFC element metadata
    // (elements + string_table — names/GUIDs, for UI/picking, never
@@ -19,12 +19,15 @@

 #include "OverlayRenderer.h"

+#include "CameraMath.h"
+
 #include <QFont>
 #include <QFontMetrics>
 #include <QImage>
 #include <QPainter>
 #include <QSet>
 #include <QStringList>
+#include <QtMath>

 #include <algorithm>
 #include <array>
@@ -46,6 +49,44 @@ WGPUStringView svFromCStr(const char* s) {
    return v;
 }

+// Populate `attribs[5]` with the standard thick-line vertex layout:
+//   loc 0: start (vec3 @ 0)   loc 1: end   (vec3 @ 12)
+//   loc 2: col   (vec3 @ 24)  loc 3: t     (f32  @ 36)
+//   loc 4: side  (f32  @ 40)
+// Returns a WGPUVertexBufferLayout aliasing the caller-owned `attribs`.
+WGPUVertexBufferLayout thickLineVertexLayout(WGPUVertexAttribute attribs[5]) {
+    attribs[0].format = WGPUVertexFormat_Float32x3; attribs[0].offset = 0;  attribs[0].shaderLocation = 0;
+    attribs[1].format = WGPUVertexFormat_Float32x3; attribs[1].offset = 12; attribs[1].shaderLocation = 1;
+    attribs[2].format = WGPUVertexFormat_Float32x3; attribs[2].offset = 24; attribs[2].shaderLocation = 2;
+    attribs[3].format = WGPUVertexFormat_Float32;   attribs[3].offset = 36; attribs[3].shaderLocation = 3;
+    attribs[4].format = WGPUVertexFormat_Float32;   attribs[4].offset = 40; attribs[4].shaderLocation = 4;
+    WGPUVertexBufferLayout vbl = {};
+    vbl.arrayStride    = 44;
+    vbl.stepMode       = WGPUVertexStepMode_Vertex;
+    vbl.attributeCount = 5;
+    vbl.attributes     = attribs;
+    return vbl;
+}
+
+// Pack the axis uniform's 256-byte slot. Layout matches WGSL AxisUniforms:
+// mat4 + vec3 + f32 + f32 + f32 + vec2 = 96 B used, padded to 256.
+void packAxisUniform(uint8_t* dst,
+                     const Eigen::Matrix4f& mvp, const Eigen::Vector3f& origin,
+                     float arm, float alpha, float line_width_px,
+                     float viewport_w, float viewport_h) {
+    std::memset(dst, 0, 256);
+    std::memcpy(dst, mvp.data(), 16 * sizeof(float));
+    float ox = origin.x(), oy = origin.y(), oz = origin.z();
+    std::memcpy(dst + 64, &ox, sizeof(float));
+    std::memcpy(dst + 68, &oy, sizeof(float));
+    std::memcpy(dst + 72, &oz, sizeof(float));
+    std::memcpy(dst + 76, &arm,           sizeof(float));
+    std::memcpy(dst + 80, &alpha,         sizeof(float));
+    std::memcpy(dst + 84, &line_width_px, sizeof(float));
+    std::memcpy(dst + 88, &viewport_w,    sizeof(float));
+    std::memcpy(dst + 92, &viewport_h,    sizeof(float));
+}
+
 }  // namespace

 // -----------------------------------------------------------------------------
@@ -85,6 +126,35 @@ fn fs_main(in: VsOut) -> @location(0) vec4<f32> {
 }
 )WGSL";

+static const std::string AXIS_WGSL = std::string(THICK_LINE_HELPERS_WGSL) + R"WGSL(
+struct AxisUniforms {
+    mvp:           mat4x4<f32>,
+    origin:        vec3<f32>,
+    arm:           f32,
+    alpha:         f32,
+    line_width_px: f32,
+    viewport_size: vec2<f32>,
+};
+
+@group(0) @binding(0) var<uniform> u: AxisUniforms;
+
+@vertex
+fn vs_main(@location(0) start: vec3<f32>,
+           @location(1) end:   vec3<f32>,
+           @location(2) col:   vec3<f32>,
+           @location(3) t:     f32,
+           @location(4) side:  f32) -> VsOut {
+    let p_start = u.mvp * vec4<f32>(u.origin + start * u.arm, 1.0);
+    let p_end   = u.mvp * vec4<f32>(u.origin + end   * u.arm, 1.0);
+    var out: VsOut;
+    out.clip_pos = thick_line_clip(p_start, p_end, t, side,
+                                    u.viewport_size, u.line_width_px);
+    out.color  = vec4<f32>(col, u.alpha);
+    out.side_t = side;
+    return out;
+}
+)WGSL";
+
 static const std::string MARQUEE_WGSL = std::string(THICK_LINE_HELPERS_WGSL) + R"WGSL(
 struct MarqueeUniforms {
    rect_min:      vec2<f32>,
@@ -313,6 +383,7 @@ bool OverlayRenderer::init(WGPUInstance instance, WGPUDevice device,
    queue_          = queue;
    surface_format_ = surface_format;
    sample_count_   = sample_count;
+    if (!buildAxisIndicator())     return false;
    // Section-plane gizmos moved to the shared SectionGizmoRenderer (ViewportCore).
    if (!buildMarquee())           return false;
    if (!buildOverlayLines())      return false;
@@ -323,6 +394,17 @@ bool OverlayRenderer::init(WGPUInstance instance, WGPUDevice device,
 }

 void OverlayRenderer::destroy() {
+    // Axis indicator
+    if (axis_bind_group_)         { wgpuBindGroupRelease(axis_bind_group_);              axis_bind_group_ = nullptr; }
+    if (axis_pivot_pipeline_)     { wgpuRenderPipelineRelease(axis_pivot_pipeline_);     axis_pivot_pipeline_ = nullptr; }
+    if (axis_pivot_xray_pipeline_){ wgpuRenderPipelineRelease(axis_pivot_xray_pipeline_); axis_pivot_xray_pipeline_ = nullptr; }
+    if (axis_corner_pipeline_)    { wgpuRenderPipelineRelease(axis_corner_pipeline_);    axis_corner_pipeline_ = nullptr; }
+    if (axis_shader_module_)      { wgpuShaderModuleRelease(axis_shader_module_);        axis_shader_module_ = nullptr; }
+    if (axis_pipeline_layout_)    { wgpuPipelineLayoutRelease(axis_pipeline_layout_);    axis_pipeline_layout_ = nullptr; }
+    if (axis_bgl_)                { wgpuBindGroupLayoutRelease(axis_bgl_);               axis_bgl_ = nullptr; }
+    if (axis_uniform_buffer_)     { wgpuBufferRelease(axis_uniform_buffer_);             axis_uniform_buffer_ = nullptr; }
+    if (axis_vertex_buffer_)      { wgpuBufferRelease(axis_vertex_buffer_);              axis_vertex_buffer_ = nullptr; }
+
    // Section visualizer

    // Marquee
@@ -384,6 +466,288 @@ void OverlayRenderer::destroy() {
    hud_text_.clear();
 }

+// -----------------------------------------------------------------------------
+// Axis indicator
+// -----------------------------------------------------------------------------
+
+bool OverlayRenderer::buildAxisIndicator() {
+    // Bonsai decorator palette (src/bonsai/bonsai/bim/ui.py:593+):
+    //   decorator_color_error    = (1.000, 0.200, 0.322) — red    → +X
+    //   decorator_color_selected = (0.545, 0.863, 0.000) — green  → +Y
+    //   decorator_color_special  = (0.157, 0.565, 1.000) — blue   → +Z
+    // Same palette is reused for the section gizmo + marquee so all overlay
+    // colours come from one canonical source.
+    static const float axis_verts[] = {
+        //  start         end           color (RGB — Bonsai decorators)  t    side
+        // ---- +X red ----
+         0,0,0,         1,0,0,        1.000f, 0.200f, 0.322f,  0.f,  -1.f,
+         0,0,0,         1,0,0,        1.000f, 0.200f, 0.322f,  0.f,  +1.f,
+         0,0,0,         1,0,0,        1.000f, 0.200f, 0.322f,  1.f,  -1.f,
+         0,0,0,         1,0,0,        1.000f, 0.200f, 0.322f,  1.f,  -1.f,
+         0,0,0,         1,0,0,        1.000f, 0.200f, 0.322f,  0.f,  +1.f,
+         0,0,0,         1,0,0,        1.000f, 0.200f, 0.322f,  1.f,  +1.f,
+        // ---- +Y green ----
+         0,0,0,         0,1,0,        0.545f, 0.863f, 0.000f,  0.f,  -1.f,
+         0,0,0,         0,1,0,        0.545f, 0.863f, 0.000f,  0.f,  +1.f,
+         0,0,0,         0,1,0,        0.545f, 0.863f, 0.000f,  1.f,  -1.f,
+         0,0,0,         0,1,0,        0.545f, 0.863f, 0.000f,  1.f,  -1.f,
+         0,0,0,         0,1,0,        0.545f, 0.863f, 0.000f,  0.f,  +1.f,
+         0,0,0,         0,1,0,        0.545f, 0.863f, 0.000f,  1.f,  +1.f,
+        // ---- +Z blue ----
+         0,0,0,         0,0,1,        0.157f, 0.565f, 1.000f,  0.f,  -1.f,
+         0,0,0,         0,0,1,        0.157f, 0.565f, 1.000f,  0.f,  +1.f,
+         0,0,0,         0,0,1,        0.157f, 0.565f, 1.000f,  1.f,  -1.f,
+         0,0,0,         0,0,1,        0.157f, 0.565f, 1.000f,  1.f,  -1.f,
+         0,0,0,         0,0,1,        0.157f, 0.565f, 1.000f,  0.f,  +1.f,
+         0,0,0,         0,0,1,        0.157f, 0.565f, 1.000f,  1.f,  +1.f,
+    };
+    {
+        WGPUBufferDescriptor bdesc = {};
+        bdesc.usage = WGPUBufferUsage_Vertex | WGPUBufferUsage_CopyDst;
+        bdesc.size  = sizeof(axis_verts);
+        bdesc.label = svFromCStr("ifcviewer-wgpu.axis_vbo");
+        axis_vertex_buffer_ = wgpuDeviceCreateBuffer(device_, &bdesc);
+        wgpuQueueWriteBuffer(queue_, axis_vertex_buffer_, 0, axis_verts, sizeof(axis_verts));
+    }
+    {
+        WGPUBufferDescriptor bdesc = {};
+        bdesc.usage = WGPUBufferUsage_Uniform | WGPUBufferUsage_CopyDst;
+        bdesc.size  = 3u * kAxisUniformSlotSize;
+        bdesc.label = svFromCStr("ifcviewer-wgpu.axis_uniforms");
+        axis_uniform_buffer_ = wgpuDeviceCreateBuffer(device_, &bdesc);
+    }
+    {
+        WGPUBindGroupLayoutEntry entry = {};
+        entry.binding    = 0;
+        entry.visibility = WGPUShaderStage_Vertex | WGPUShaderStage_Fragment;
+        entry.buffer.type             = WGPUBufferBindingType_Uniform;
+        entry.buffer.hasDynamicOffset = 1;
+        entry.buffer.minBindingSize   = 96;
+        WGPUBindGroupLayoutDescriptor bgl_desc = {};
+        bgl_desc.entryCount = 1;
+        bgl_desc.entries    = &entry;
+        bgl_desc.label      = svFromCStr("ifcviewer-wgpu.axis_bgl");
+        axis_bgl_ = wgpuDeviceCreateBindGroupLayout(device_, &bgl_desc);
+    }
+    {
+        WGPUPipelineLayoutDescriptor pl_desc = {};
+        pl_desc.bindGroupLayoutCount = 1;
+        pl_desc.bindGroupLayouts     = &axis_bgl_;
+        pl_desc.label                = svFromCStr("ifcviewer-wgpu.axis_pipeline_layout");
+        axis_pipeline_layout_ = wgpuDeviceCreatePipelineLayout(device_, &pl_desc);
+    }
+    {
+        WGPUBindGroupEntry entry = {};
+        entry.binding = 0;
+        entry.buffer  = axis_uniform_buffer_;
+        entry.offset  = 0;
+        entry.size    = kAxisUniformSlotSize;
+        WGPUBindGroupDescriptor bg_desc = {};
+        bg_desc.layout     = axis_bgl_;
+        bg_desc.entryCount = 1;
+        bg_desc.entries    = &entry;
+        bg_desc.label      = svFromCStr("ifcviewer-wgpu.axis_bind_group");
+        axis_bind_group_ = wgpuDeviceCreateBindGroup(device_, &bg_desc);
+    }
+    {
+        WGPUShaderSourceWGSL wgsl_src = {};
+        wgsl_src.chain.sType = WGPUSType_ShaderSourceWGSL;
+        wgsl_src.code        = svFromCStr(AXIS_WGSL.c_str());
+        WGPUShaderModuleDescriptor sm_desc = {};
+        sm_desc.nextInChain = &wgsl_src.chain;
+        sm_desc.label       = svFromCStr("ifcviewer-wgpu.axis_wgsl");
+        axis_shader_module_ = wgpuDeviceCreateShaderModule(device_, &sm_desc);
+    }
+
+    WGPUVertexAttribute attribs[5] = {};
+    WGPUVertexBufferLayout vbl = thickLineVertexLayout(attribs);
+
+    WGPUBlendState blend = {};
+    blend.color.srcFactor = WGPUBlendFactor_SrcAlpha;
+    blend.color.dstFactor = WGPUBlendFactor_OneMinusSrcAlpha;
+    blend.color.operation = WGPUBlendOperation_Add;
+    blend.alpha.srcFactor = WGPUBlendFactor_One;
+    blend.alpha.dstFactor = WGPUBlendFactor_OneMinusSrcAlpha;
+    blend.alpha.operation = WGPUBlendOperation_Add;
+
+    auto build_pivot = [&](WGPUCompareFunction cmp, const char* label,
+                           WGPURenderPipeline& out) {
+        WGPUColorTargetState ct = {};
+        ct.format    = surface_format_;
+        ct.blend     = &blend;
+        ct.writeMask = WGPUColorWriteMask_All;
+
+        WGPUFragmentState frag = {};
+        frag.module      = axis_shader_module_;
+        frag.entryPoint  = svFromCStr("fs_main");
+        frag.targetCount = 1;
+        frag.targets     = &ct;
+
+        WGPUDepthStencilState depth = {};
+        depth.format               = WGPUTextureFormat_Depth32Float;
+        depth.depthWriteEnabled    = WGPUOptionalBool_False;
+        depth.depthCompare         = cmp;
+        depth.stencilFront.compare = WGPUCompareFunction_Always;
+        depth.stencilBack.compare  = WGPUCompareFunction_Always;
+
+        WGPURenderPipelineDescriptor rp_desc = {};
+        rp_desc.layout              = axis_pipeline_layout_;
+        rp_desc.label               = svFromCStr(label);
+        rp_desc.vertex.module       = axis_shader_module_;
+        rp_desc.vertex.entryPoint   = svFromCStr("vs_main");
+        rp_desc.vertex.bufferCount  = 1;
+        rp_desc.vertex.buffers      = &vbl;
+        rp_desc.fragment            = &frag;
+        rp_desc.depthStencil        = &depth;
+        rp_desc.primitive.topology  = WGPUPrimitiveTopology_TriangleList;
+        rp_desc.primitive.cullMode  = WGPUCullMode_None;
+        rp_desc.multisample.count   = uint32_t(sample_count_);
+        rp_desc.multisample.mask    = 0xFFFFFFFFu;
+        out = wgpuDeviceCreateRenderPipeline(device_, &rp_desc);
+    };
+    build_pivot(WGPUCompareFunction_LessEqual,
+                "ifcviewer-wgpu.axis_pivot_pipeline",
+                axis_pivot_pipeline_);
+    build_pivot(WGPUCompareFunction_GreaterEqual,
+                "ifcviewer-wgpu.axis_pivot_xray_pipeline",
+                axis_pivot_xray_pipeline_);
+
+    // Corner: resolved surface, no depth, sampleCount=1.
+    {
+        WGPUColorTargetState ct = {};
+        ct.format    = surface_format_;
+        ct.blend     = &blend;
+        ct.writeMask = WGPUColorWriteMask_All;
+
+        WGPUFragmentState frag = {};
+        frag.module      = axis_shader_module_;
+        frag.entryPoint  = svFromCStr("fs_main");
+        frag.targetCount = 1;
+        frag.targets     = &ct;
+
+        WGPURenderPipelineDescriptor rp_desc = {};
+        rp_desc.layout              = axis_pipeline_layout_;
+        rp_desc.label               = svFromCStr("ifcviewer-wgpu.axis_corner_pipeline");
+        rp_desc.vertex.module       = axis_shader_module_;
+        rp_desc.vertex.entryPoint   = svFromCStr("vs_main");
+        rp_desc.vertex.bufferCount  = 1;
+        rp_desc.vertex.buffers      = &vbl;
+        rp_desc.fragment            = &frag;
+        rp_desc.primitive.topology  = WGPUPrimitiveTopology_TriangleList;
+        rp_desc.primitive.cullMode  = WGPUCullMode_None;
+        rp_desc.multisample.count   = 1;
+        rp_desc.multisample.mask    = 0xFFFFFFFFu;
+        axis_corner_pipeline_ = wgpuDeviceCreateRenderPipeline(device_, &rp_desc);
+    }
+
+    return axis_pivot_pipeline_ && axis_pivot_xray_pipeline_
+        && axis_corner_pipeline_;
+}
+
+void OverlayRenderer::encodePivot(WGPURenderPassEncoder pass,
+                                      const OverlayFrame& f,
+                                      bool visible) {
+    if (!visible || !axis_pivot_pipeline_ || !axis_pivot_xray_pipeline_) return;
+    if (f.viewport_h_px <= 0) return;
+
+    // Arm length = 30 logical px projected into world at the pivot's distance.
+    const float fovy_rad        = qDegreesToRadians(f.camera_fov_y_deg);
+    const float world_per_pixel = f.camera_distance * std::tan(fovy_rad * 0.5f)
+                                  * 2.0f / float(f.viewport_h_px);
+    const float arm_pixels = 30.0f * float(f.device_pixel_ratio);
+    const float arm_world  = arm_pixels * world_per_pixel;
+
+    const float dpr     = float(f.device_pixel_ratio);
+    const float line_w  = 2.5f * dpr;
+    const float vw      = float(f.viewport_w_px);
+    const float vh      = float(f.viewport_h_px);
+
+    uint8_t slot_visible[256];
+    uint8_t slot_xray[256];
+    packAxisUniform(slot_visible, f.view_proj, f.camera_target, arm_world,
+                    1.00f, line_w, vw, vh);
+    packAxisUniform(slot_xray,    f.view_proj, f.camera_target, arm_world,
+                    0.30f, line_w, vw, vh);
+    const uint32_t visible_off = 1u * kAxisUniformSlotSize;
+    const uint32_t xray_off    = 2u * kAxisUniformSlotSize;
+    wgpuQueueWriteBuffer(queue_, axis_uniform_buffer_, visible_off,
+                         slot_visible, sizeof(slot_visible));
+    wgpuQueueWriteBuffer(queue_, axis_uniform_buffer_, xray_off,
+                         slot_xray, sizeof(slot_xray));
+
+    wgpuRenderPassEncoderSetVertexBuffer(pass, 0, axis_vertex_buffer_, 0,
+                                         WGPU_WHOLE_SIZE);
+    wgpuRenderPassEncoderSetPipeline(pass, axis_pivot_xray_pipeline_);
+    wgpuRenderPassEncoderSetBindGroup(pass, 0, axis_bind_group_, 1, &xray_off);
+    wgpuRenderPassEncoderDraw(pass, 18, 1, 0, 0);
+    wgpuRenderPassEncoderSetPipeline(pass, axis_pivot_pipeline_);
+    wgpuRenderPassEncoderSetBindGroup(pass, 0, axis_bind_group_, 1, &visible_off);
+    wgpuRenderPassEncoderDraw(pass, 18, 1, 0, 0);
+}
+
+void OverlayRenderer::encodeCornerAxis(WGPUCommandEncoder enc,
+                                           WGPUTextureView surface_view,
+                                           const OverlayFrame& f) {
+    if (!axis_corner_pipeline_ || !surface_view) return;
+    const int dpr = std::max(1, f.device_pixel_ratio);
+    const uint32_t gizmo_size = uint32_t(110 * dpr);
+    const uint32_t margin     = uint32_t(10 * dpr);
+    if (gizmo_size == 0 || f.viewport_w_px <= 0 || f.viewport_h_px <= 0) return;
+    // Bottom-left in WebGPU framebuffer space (y down).
+    const uint32_t fb_h = uint32_t(f.viewport_h_px);
+    if (gizmo_size + margin > fb_h) return;
+    const uint32_t y = fb_h - margin - gizmo_size;
+
+    // Independent ortho projection from the camera's direction. Near the
+    // poles the up axis collapses against the look direction, so swap to
+    // Y-up there — mirrors buildViewProj's identical fix on the viewport.
+    const float yaw_rad   = qDegreesToRadians(f.camera_yaw_deg);
+    const float pitch_rad = qDegreesToRadians(f.camera_pitch_deg);
+    const Eigen::Vector3f eye_dir(std::cos(pitch_rad) * std::cos(yaw_rad),
+                            std::cos(pitch_rad) * std::sin(yaw_rad),
+                            std::sin(pitch_rad));
+    const Eigen::Vector3f world_up = (std::abs(f.camera_pitch_deg) >= 89.0f)
+                                 ? Eigen::Vector3f(0.0f, 1.0f, 0.0f)
+                                 : Eigen::Vector3f(0.0f, 0.0f, 1.0f);
+    const Eigen::Matrix4f gv = lookAtRH(eye_dir * 3.0f, Eigen::Vector3f::Zero(), world_up);
+    const Eigen::Matrix4f gp = orthoGL(-1.4f, 1.4f, -1.4f, 1.4f, 0.1f, 10.0f);
+    Eigen::Matrix4f z_remap = Eigen::Matrix4f::Identity();
+    z_remap(2, 2) = 0.5f;
+    z_remap(2, 3) = 0.5f;
+    const Eigen::Matrix4f mvp = z_remap * gp * gv;
+
+    uint8_t slot[256];
+    const float line_w = 2.5f * float(dpr);
+    packAxisUniform(slot, mvp, Eigen::Vector3f(0, 0, 0), 1.0f, 1.0f, line_w,
+                    float(gizmo_size), float(gizmo_size));
+    const uint32_t slot_offset = 0u;
+    wgpuQueueWriteBuffer(queue_, axis_uniform_buffer_, slot_offset, slot, sizeof(slot));
+
+    WGPURenderPassColorAttachment color = {};
+    color.view       = surface_view;
+    color.loadOp     = WGPULoadOp_Load;
+    color.storeOp    = WGPUStoreOp_Store;
+    color.clearValue = { 0.0, 0.0, 0.0, 1.0 };
+    color.depthSlice = WGPU_DEPTH_SLICE_UNDEFINED;
+
+    WGPURenderPassDescriptor pass_desc = {};
+    pass_desc.colorAttachmentCount = 1;
+    pass_desc.colorAttachments     = &color;
+    pass_desc.label                = svFromCStr("ifcviewer-wgpu.corner_axis_pass");
+
+    WGPURenderPassEncoder pass = wgpuCommandEncoderBeginRenderPass(enc, &pass_desc);
+    wgpuRenderPassEncoderSetViewport(pass, float(margin), float(y),
+                                     float(gizmo_size), float(gizmo_size),
+                                     0.0f, 1.0f);
+    wgpuRenderPassEncoderSetPipeline(pass, axis_corner_pipeline_);
+    wgpuRenderPassEncoderSetVertexBuffer(pass, 0, axis_vertex_buffer_, 0,
+                                         WGPU_WHOLE_SIZE);
+    wgpuRenderPassEncoderSetBindGroup(pass, 0, axis_bind_group_, 1, &slot_offset);
+    wgpuRenderPassEncoderDraw(pass, 18, 1, 0, 0);
+    wgpuRenderPassEncoderEnd(pass);
+    wgpuRenderPassEncoderRelease(pass);
+}
+
 // -----------------------------------------------------------------------------
 // Marquee
 // -----------------------------------------------------------------------------
@@ -33,14 +33,10 @@
 #include "OverlayFrame.h"
 #include "SectionPlane.h"

-// The Qt-coupled viewport overlays: the marquee drag rect, measure-tool
-// lines / points / highlight patches, and the QPainter-rasterised labels
-// and HUD. Mirrors GL's OverlayRenderer split so ViewportWindow.cpp
-// doesn't have to carry ~1.5k lines of pipeline plumbing.
-//
-// The Qt-free overlays live in their own shared renderers so the web build
-// gets them too: SectionGizmoRenderer and AxisIndicatorRenderer (corner
-// axis gizmo + orbit pivot), both driven by ViewportCore::render.
+// All viewport overlays in one place: axis indicator (corner + pivot),
+// section plane gizmos, and the marquee drag rect. Mirrors GL's
+// OverlayRenderer split so ViewportWindow.cpp doesn't have to
+// carry ~1.5k lines of pipeline plumbing.
 //
 // Lifecycle: init() once after the device is up, destroy() before the
 // device dies. Pipelines are immutable after init; only per-frame
@@ -60,11 +56,16 @@ public:
    void destroy();

    // ---- Inside the main MSAA pass, after geometry ----
-    // These share depth with the scene so they're correctly occluded.
+    // Both share depth with the scene so they're correctly occluded.

-    // Section-plane gizmos moved to the shared SectionGizmoRenderer, and the
-    // orbit pivot to AxisIndicatorRenderer (both drawn by ViewportCore for
-    // desktop + web).
+    // Orbit pivot indicator. `visible` is the viewport's UI gate (orbit
+    // drag / wheel-zoom afterglow). When false this is a cheap no-op.
+    void encodePivot(WGPURenderPassEncoder pass,
+                     const OverlayFrame& f,
+                     bool visible);
+
+    // Section-plane gizmos moved to the shared SectionGizmoRenderer (drawn by
+    // ViewportCore for both desktop + web).

    // Replace the highlight-triangle list. `world_xyz` is 3 floats per
    // vertex, 3 vertices per triangle, in world space (post-composed-
@@ -147,8 +148,12 @@ public:
                      const OverlayFrame& f);

    // ---- After the edge silhouette pass, on the resolved surface ----
-    // (The corner axis gizmo also draws here — from ViewportCore, via
-    // AxisIndicatorRenderer.)
+
+    // Corner axis gizmo (bottom-left, 110×110 px). Independent ortho
+    // projection — only the camera direction matters.
+    void encodeCornerAxis(WGPUCommandEncoder enc,
+                          WGPUTextureView surface_view,
+                          const OverlayFrame& f);

    // Marquee box-select drag rect (translucent fill + thick outline).
    // No-op when `active` is false.
@@ -165,6 +170,7 @@ public:
    static constexpr int kMaxSectionPlanes = 6;

 private:
+    bool buildAxisIndicator();
    bool buildMarquee();
    bool buildOverlayLines();
    bool buildOverlayPoints();
@@ -194,6 +200,19 @@ private:
    WGPUTextureFormat   surface_format_ = WGPUTextureFormat_Undefined;
    int                 sample_count_   = 1;

+    // ---- Axis indicator (shared shape, three pipelines) ----
+    // Slot 0 = corner gizmo. Slots 1/2 = pivot visible/x-ray.
+    WGPUShaderModule    axis_shader_module_       = nullptr;
+    WGPUBindGroupLayout axis_bgl_                 = nullptr;
+    WGPUPipelineLayout  axis_pipeline_layout_     = nullptr;
+    WGPURenderPipeline  axis_pivot_pipeline_      = nullptr;
+    WGPURenderPipeline  axis_pivot_xray_pipeline_ = nullptr;
+    WGPURenderPipeline  axis_corner_pipeline_     = nullptr;
+    WGPUBuffer          axis_vertex_buffer_       = nullptr;
+    WGPUBuffer          axis_uniform_buffer_      = nullptr;
+    WGPUBindGroup       axis_bind_group_          = nullptr;
+    static constexpr uint32_t kAxisUniformSlotSize = 256;
+
    // ---- Marquee (fill + outline pipelines, one uniform buffer) ----
    WGPUShaderModule    marquee_shader_module_      = nullptr;
    WGPUBindGroupLayout marquee_bgl_                = nullptr;
@@ -576,21 +576,6 @@ void ViewportCore::dollyBy(float notches) {
    host_->requestFrame();
 }

-void ViewportCore::setPivotIndicatorVisible(bool visible, int hide_after_ms) {
-    pivot_indicator_visible_ = visible;
-    pivot_indicator_hide_ms_ = hide_after_ms;
-    if (visible && hide_after_ms > 0) pivot_indicator_timer_.start();
-    else                              pivot_indicator_timer_.invalidate();
-    host_->requestFrame();
-}
-
-bool ViewportCore::pivotIndicatorVisible() const {
-    if (!pivot_indicator_visible_) return false;
-    // No armed afterglow means a drag is holding it up.
-    if (!pivot_indicator_timer_.isValid()) return true;
-    return pivot_indicator_timer_.elapsed() < pivot_indicator_hide_ms_;
-}
-
 void ViewportCore::flyMove(bool fwd, bool back, bool right, bool left,
                           bool up, bool down, bool boost, float dt_seconds) {
    if (dt_seconds <= 0.0f) return;
@@ -1312,10 +1297,6 @@ bool ViewportCore::buildPipelines() {
    // Section-plane gizmo (shared desktop + web). Optional — a failure just
    // means no gizmo, not a dead viewport.
    section_gizmo_.init(device_, queue_, surface_view_format_, kViewportSampleCount);
-
-    // Corner axis gizmo + orbit pivot indicator (shared desktop + web).
-    // Also optional: a failure costs the indicator, not the viewport.
-    axis_indicator_.init(device_, queue_, surface_view_format_, kViewportSampleCount);
    return true;
 }

@@ -1932,7 +1913,6 @@ void ViewportCore::shutdown() {
    if (main_pipeline_no_cull_)      { wgpuRenderPipelineRelease(main_pipeline_no_cull_);     main_pipeline_no_cull_ = nullptr; }
    if (main_pipeline_transparent_)  { wgpuRenderPipelineRelease(main_pipeline_transparent_); main_pipeline_transparent_ = nullptr; }
    section_gizmo_.destroy();
-    axis_indicator_.destroy();
    if (main_shader_module_)   { wgpuShaderModuleRelease(main_shader_module_);    main_shader_module_ = nullptr; }
    if (pipeline_layout_)      { wgpuPipelineLayoutRelease(pipeline_layout_);     pipeline_layout_ = nullptr; }
    if (model_bgl_)            { wgpuBindGroupLayoutRelease(model_bgl_);          model_bgl_ = nullptr; }
@@ -3898,24 +3878,10 @@ void ViewportCore::loadSidecarMetadataWeb(int source_id, std::string source_labe
        return;
    }

-    // Mint the session model id HERE, synchronously, rather than at the end of
-    // the read chain below. Session ids are what orders the scene's models —
-    // modelIdsInLoadOrder sorts by them, and every per-model slot a host sees
-    // (modelProgress's index, ElementRef::model_index) is a rank in that order.
-    // Minting on completion made that rank the order the models' network reads
-    // happened to finish in, so with several federated models in flight the
-    // slots came out shuffled against the order the host added them and a pick
-    // was attributed to the wrong file. Requesting order is the order the host
-    // asked for, which is the order it can reason about. A load that fails
-    // partway simply abandons its id — the ranks compact over whatever models
-    // made it into the scene, exactly as before.
-    const std::uint32_t session_model_id = next_session_model_id_++;
-
    // Head (v16): [header 12][geom_bytes 8]. The two compressed metadata blocks
    // follow the compressed geometry at SIDECAR_HEAD_BYTES + geom_bytes.
    webReadRangesAsync(source_id, 0, {{0, SIDECAR_HEAD_BYTES}},
-        [this, fsize, source_id, source_label, session_model_id,
-         on_loaded = std::move(on_loaded)]
+        [this, fsize, source_id, source_label, on_loaded = std::move(on_loaded)]
        (bool ok, std::vector<std::uint8_t>&& head) mutable {
            std::uint64_t geom_bytes = 0;
            if (!ok || !parseSidecarHead(head.data(), head.size(), geom_bytes)) {
@@ -3929,7 +3895,7 @@ void ViewportCore::loadSidecarMetadataWeb(int source_id, std::string source_labe
            }
            // Geometry metadata block on disk: [comp u64][raw u64][zstd frame].
            webReadRangesAsync(source_id, 0, {{meta_off, 16}},
-                [this, fsize, meta_off, source_id, source_label, session_model_id,
+                [this, fsize, meta_off, source_id, source_label,
                 on_loaded = std::move(on_loaded)]
                (bool ok2, std::vector<std::uint8_t>&& h) {
                    if (!ok2 || h.size() < 16) {
@@ -3948,7 +3914,7 @@ void ViewportCore::loadSidecarMetadataWeb(int source_id, std::string source_labe
                        {{geometry_metadata_off, geometry_metadata_comp}},
                        [this, geometry_metadata_off, geometry_metadata_comp,
                         geometry_metadata_raw, source_id, source_label,
-                         session_model_id, on_loaded = std::move(on_loaded)]
+                         on_loaded = std::move(on_loaded)]
                        (bool ok3, std::vector<std::uint8_t>&& cz) {
                            if (!ok3) {
                                Log::warn() << "loadSidecarMetadataWeb: geometry metadata read failed";
@@ -3985,7 +3951,7 @@ void ViewportCore::loadSidecarMetadataWeb(int source_id, std::string source_labe
                                geometry_metadata_off + geometry_metadata_comp;
                            webReadRangesAsync(source_id, 0, {{element_metadata_hdr_off, 16}},
                                [this, sc = std::move(sc), element_metadata_hdr_off,
-                                 source_id, source_label, session_model_id,
+                                 source_id, source_label,
                                 on_loaded = std::move(on_loaded)]
                                (bool ok4, std::vector<std::uint8_t>&& dh) mutable {
                                    if (ok4 && dh.size() >= 16) {
@@ -4003,6 +3969,7 @@ void ViewportCore::loadSidecarMetadataWeb(int source_id, std::string source_labe

                                    const std::size_t n_meshes    = sc.meta.meshes.size();
                                    const std::size_t n_instances = sc.meta.instances.size();
+                                    const std::uint32_t session_model_id = next_session_model_id_++;
                                    applyCachedModel(session_model_id, std::move(sc));
                                    // Mark web-streamed + set the source IMMEDIATELY — the
                                    // model now has non-resident chunks and the RAF loop's
@@ -4104,14 +4071,11 @@ void ViewportCore::logSelectedObjectGuidWeb(std::uint32_t object_id) {
        }
        Log::info() << "pick: object " << object_id << " GUID " << e.guid;
        // Surface the selection to JS so host pages can react (e.g. show the
-        // GUID + model). Fires
-        // Module.__ifcvOnSelect(object_id, guid, modelIndex, sourceId).
-        // modelIndex is the load-order slot; sourceId is the byte-source the
-        // host added the model from, which is the one that cannot shift.
+        // GUID + model). Fires Module.__ifcvOnSelect(object_id, guid, modelIndex);
+        // model_index is the load-order slot, matching the JS model list.
        EM_ASM({
-            if (Module.__ifcvOnSelect)
-                Module.__ifcvOnSelect($0, UTF8ToString($1), $2, $3);
-        }, object_id, e.guid.c_str(), e.model_index, e.source_id);
+            if (Module.__ifcvOnSelect) Module.__ifcvOnSelect($0, UTF8ToString($1), $2);
+        }, object_id, e.guid.c_str(), e.model_index);
    });
 }
 #endif  // __EMSCRIPTEN__
@@ -4173,7 +4137,6 @@ ViewportCore::ElementRef makeElementRef(const ModelGpuData& m, int model_index,
    ViewportCore::ElementRef ref;
    ref.object_id   = e.object_id;
    ref.model_index = model_index;
-    ref.source_id   = m.web_source_id;
    ref.guid        = str(e.guid_offset, e.guid_length);
    ref.name        = str(e.name_offset, e.name_length);
    ref.type        = str(e.type_offset, e.type_length);
@@ -7643,15 +7606,8 @@ void ViewportCore::render() {
    section_gizmo_.encode(pass, vp_this_frame, section_planes_,
                          viewport_w_px, viewport_h_px, dpr_int, section_selected_index_);

-    // Orbit pivot indicator — same shared-renderer story. Drawn while the host
-    // has it gated on (drag) or an afterglow is still running; in the latter
-    // case keep frames coming so the one that clears it actually lands.
-    const bool pivot_visible = pivotIndicatorVisible();
-    axis_indicator_.encodePivot(pass, overlay_frame, pivot_visible);
-    if (pivot_visible && pivot_indicator_timer_.isValid()) host_->requestFrame();
-
-    // Remaining in-pass overlays (highlight triangles, overlay lines/points).
-    // QtViewportHost forwards to overlays_.X(); the web host no-ops.
+    // Remaining in-pass overlays (highlight triangles, pivot, overlay
+    // lines/points). QtViewportHost forwards to overlays_.X(); web host no-ops.
    host_->encodeOverlaysInMainPass(pass, overlay_frame);

    wgpuRenderPassEncoderEnd(pass);
@@ -7670,12 +7626,8 @@ void ViewportCore::render() {
    int hiz_submitted_slot = -1;
    if (hiz_enabled_) hiz_submitted_slot = encodeHizResolve(enc);

-    // Corner axis gizmo on the resolved surface — shared renderer, ahead of the
-    // host's own post-main overlays so marquee / labels still stack on top.
-    axis_indicator_.encodeCornerAxis(enc, view, overlay_frame);
-
-    // Remaining post-main overlays (marquee, labels) on the resolved surface.
-    // QtViewportHost forwards to overlays_.X(); the web host no-ops.
+    // Post-main overlays (corner axis, marquee, labels) on the resolved
+    // surface. QtViewportHost forwards to overlays_.X().
    host_->encodeOverlaysPostMain(enc, view, overlay_frame);

    // Optional capture: encode copy on the same command buffer.
@@ -47,7 +47,6 @@
 #include <utility>
 #include <vector>

-#include "AxisIndicatorRenderer.h"
 #include "BufferPool.h"
 #include "InstanceCompose.h"
 #include "InstancedGeometry.h"
@@ -56,7 +55,6 @@
 #include "SectionPlane.h"
 #include "SelectionState.h"
 #include "SidecarCache.h"
-#include "Stopwatch.h"
 #include "StreamingLoader.h"
 #include "StreamingThread.h"
 #include "ViewportHost.h"
@@ -283,9 +281,9 @@ public:
    //
    // Pixel-delta camera moves, shared by every host (Qt desktop + web).
    // Hosts translate raw pointer/wheel events into these calls and own
-    // their own UI concerns (drag promotion, cursor capture); the orbit
-    // math lives here so it can't drift between platforms. Each schedules
-    // a frame via the host.
+    // their own UI concerns (drag promotion, pivot indicator, cursor
+    // capture); the orbit math lives here so it can't drift between
+    // platforms. Each schedules a frame via the host.
    //
    // orbitBy:  drag-right yaws the world right (yaw -= dx), drag-down
    //           tilts the camera up (pitch += dy). 0.4 deg/px matches GL.
@@ -298,18 +296,6 @@ public:
    void panBy(float dx_px, float dy_px, int viewport_height_px);
    void dollyBy(float notches);

-    // ---- Pivot indicator ----------------------------------------------------
-    //
-    // The RGB triad drawn at the orbit target while the user navigates, so it's
-    // obvious what the camera is turning around. Hosts gate it: (true) when an
-    // orbit / pan drag starts, (false) when it ends. `hide_after_ms` > 0 arms an
-    // afterglow instead — the wheel path uses it so a zoom without a held drag
-    // still shows the pivot for a moment. State lives here (not in the host) so
-    // desktop and web behave identically; render() consults it each frame and
-    // keeps requesting frames until an armed afterglow expires.
-    void setPivotIndicatorVisible(bool visible, int hide_after_ms = 0);
-    bool pivotIndicatorVisible() const;
-
    // ---- First-person / fly navigation --------------------------------------
    //
    // Shared fly-camera math (desktop + web). The HOST owns the fly-mode flag,
@@ -544,10 +530,8 @@ public:

    // Per-model progress for a federation loading UI. count() is how many
    // models have metadata (are in the scene); progress(idx,…) gives the
-    // idx-th model's resident/total chunks, ordered by session_model_id — which
-    // is minted when a load is REQUESTED, so this is the order the host asked
-    // for its models, not the order their reads finished. Each model keeps a
-    // stable UI slot as it streams.
+    // idx-th model's resident/total chunks, ordered by session_model_id (= load order)
+    // so each model keeps a stable UI slot as it streams.
    int  streamingModelCount() const;
    void streamingModelProgress(int idx, int& resident_chunks,
                                int& total_chunks) const;
@@ -558,17 +542,11 @@ public:
    int modelLoadIndex(std::uint32_t session_model_id) const;

    // One row of the element table: the IFC identity behind a rendered
-    // object_id, plus which model it came from, said two ways.
-    //
-    // `model_index` is the load-order slot (modelLoadIndex) — a POSITION, so it
-    // shifts if an earlier model fails to load. `source_id` is the JS byte-source
-    // the model was added from (-1 when it came from somewhere else), which the
-    // host minted itself and which never moves. Prefer the latter for
-    // attributing an object to a file; the index is for UI slots.
+    // object_id. `model_index` is the load-order slot (modelLoadIndex), so a
+    // host UI can attribute an object to the file it came from.
    struct ElementRef {
        std::uint32_t object_id   = 0;
        int           model_index = -1;
-        int           source_id   = -1;
        std::string   guid;
        std::string   name;
        std::string   type;
@@ -1052,10 +1030,9 @@ public:
 private:
    bool createPool();

-    // The scene's models in load order (ascending session_model_id, minted at
-    // request time — see loadSidecarMetadataWeb). Every per-model API indexes
-    // against this, so a model keeps a stable UI slot instead of hopping with
-    // unordered_map iteration order.
+    // The scene's models in load order (ascending session_model_id). Every
+    // per-model API indexes against this, so a model keeps a stable UI slot
+    // instead of hopping with unordered_map iteration order.
    std::vector<std::uint32_t> modelIdsInLoadOrder() const;

 public:
@@ -1115,14 +1092,6 @@ private:
    // Lifted out of the Qt-coupled OverlayRenderer so one identical gizmo draws
    // everywhere; the desktop's OverlayRenderer no longer draws it.
    SectionGizmoRenderer section_gizmo_;
-    // Corner axis gizmo + orbit pivot indicator, likewise shared by desktop +
-    // web. Same lift out of the Qt-coupled OverlayRenderer.
-    AxisIndicatorRenderer axis_indicator_;
-    bool                  pivot_indicator_visible_ = false;
-    // Only running while an afterglow is armed; a drag-held indicator leaves it
-    // invalid so the triad stays up until the host clears it.
-    Stopwatch             pivot_indicator_timer_;
-    int                   pivot_indicator_hide_ms_ = 0;

    // HiZ occlusion-cull pipeline group. Downsamples MSAA depth into a
    // mip pyramid; consumed by next-frame cull.
@@ -435,14 +435,14 @@ void ViewportWindow::onFrameStats(const FrameStats& stats) {

 void ViewportWindow::encodeOverlaysInMainPass(WGPURenderPassEncoder pass,
                                              const OverlayFrame& frame) {
-    // Highlight triangles + overlay lines / points — drawn inside the MSAA
-    // pass so depth-test correctly hides them behind closer geometry.
-    // (Marquee / labels run on the resolved surface; see
-    // encodeOverlaysPostMain.)
-    // NB: section-plane gizmos and the pivot indicator now draw from
-    // ViewportCore::render via their shared renderers (desktop + web), so
-    // they are NOT drawn here.
+    // Section gizmos, highlight triangles, pivot, overlay lines / points
+    // — drawn inside the MSAA pass so depth-test correctly hides them
+    // behind closer geometry. (Corner axis / marquee / labels run on the
+    // resolved surface; see encodeOverlaysPostMain.)
+    // NB: section-plane gizmos now draw from ViewportCore::render via the shared
+    // SectionGizmoRenderer (desktop + web), so they are NOT drawn here.
    overlays_.encodeHighlightTriangles(pass, frame);
+    overlays_.encodePivot(pass, frame, pivot_indicator_visible_);
    overlays_.encodeOverlayLines(pass, frame);
    overlays_.encodeOverlayPoints(pass, frame);
 }
@@ -450,8 +450,7 @@ void ViewportWindow::encodeOverlaysInMainPass(WGPURenderPassEncoder pass,
 void ViewportWindow::encodeOverlaysPostMain(WGPUCommandEncoder enc,
                                            WGPUTextureView surface_view,
                                            const OverlayFrame& frame) {
-    // NB: the corner axis gizmo draws from ViewportCore::render (shared
-    // AxisIndicatorRenderer), just before this hook.
+    overlays_.encodeCornerAxis(enc, surface_view, frame);
    overlays_.encodeMarquee(enc, surface_view, frame,
                            box_select_start_pos_,
                            box_select_current_pos_,
@@ -908,8 +907,25 @@ bool ViewportWindow::initWgpu() {

 // encodeEdgePass moved to ViewportCore (#84-s).

-// setPivotIndicatorVisible moved to ViewportCore (drawn by the shared
-// AxisIndicatorRenderer, so the visibility gate lives there too).
+// -----------------------------------------------------------------------------
+void ViewportWindow::setPivotIndicatorVisible(bool visible, int hide_after_ms) {
+    if (!pivot_indicator_hide_timer_) {
+        pivot_indicator_hide_timer_ = new QTimer(this);
+        pivot_indicator_hide_timer_->setSingleShot(true);
+        QObject::connect(pivot_indicator_hide_timer_, &QTimer::timeout, this,
+                         [this]() {
+                             pivot_indicator_visible_ = false;
+                             requestUpdate();
+                         });
+    }
+    pivot_indicator_visible_ = visible;
+    if (visible && hide_after_ms > 0) {
+        pivot_indicator_hide_timer_->start(hide_after_ms);
+    } else {
+        pivot_indicator_hide_timer_->stop();
+    }
+    requestUpdate();
+}
 // releaseEdgeResources moved to ViewportCore (#84-s).

 // -----------------------------------------------------------------------------
@@ -1569,11 +1585,11 @@ void ViewportWindow::mousePressEvent(QMouseEvent* event) {
    if (event->button() == orbit_button_
        && (mods & Qt::KeyboardModifierMask) == orbit_mods_) {
        nav_drag_kind_ = NavDrag::Orbit;
-        core_.setPivotIndicatorVisible(true);  // hidden again on release
+        setPivotIndicatorVisible(true);  // hidden again on release
    } else if (event->button() == pan_button_
            && (mods & Qt::KeyboardModifierMask) == pan_mods_) {
        nav_drag_kind_ = NavDrag::Pan;
-        core_.setPivotIndicatorVisible(true);
+        setPivotIndicatorVisible(true);
    } else if (event->button() == select_button_
            && !section_tool_active_
            && tool_mode_ != ToolMode::Area
@@ -1667,7 +1683,7 @@ void ViewportWindow::mouseReleaseEvent(QMouseEvent* event) {
                }
                nav_active_button_ = Qt::NoButton;
                nav_drag_kind_     = NavDrag::Inactive;
-                core_.setPivotIndicatorVisible(false);
+                setPivotIndicatorVisible(false);
                return;
            }

@@ -1684,7 +1700,7 @@ void ViewportWindow::mouseReleaseEvent(QMouseEvent* event) {
                emit surfacePickedInTool(px, py, int(event->modifiers()));
                nav_active_button_ = Qt::NoButton;
                nav_drag_kind_     = NavDrag::Inactive;
-                core_.setPivotIndicatorVisible(false);
+                setPivotIndicatorVisible(false);
                return;
            }

@@ -1699,7 +1715,7 @@ void ViewportWindow::mouseReleaseEvent(QMouseEvent* event) {
                emit surfacePickedInTool(px, py, int(event->modifiers()));
                nav_active_button_ = Qt::NoButton;
                nav_drag_kind_     = NavDrag::Inactive;
-                core_.setPivotIndicatorVisible(false);
+                setPivotIndicatorVisible(false);
                return;
            }

@@ -1784,7 +1800,7 @@ void ViewportWindow::mouseReleaseEvent(QMouseEvent* event) {
        nav_active_button_ = Qt::NoButton;
        nav_drag_kind_     = NavDrag::Inactive;
        // Drag is over — hide the pivot indicator without afterglow.
-        core_.setPivotIndicatorVisible(false);
+        setPivotIndicatorVisible(false);
    }
 }

@@ -2034,7 +2050,7 @@ void ViewportWindow::wheelEvent(QWheelEvent* event) {
    core_.dollyBy(notches);
    // Pivot afterglow on wheel — visible for 600 ms so the user can see
    // what they're zooming around without holding a drag.
-    core_.setPivotIndicatorVisible(true, 600);
+    setPivotIndicatorVisible(true, 600);
 }

 void ViewportWindow::shutdown() {
@@ -21,6 +21,7 @@
 #define WGPUVIEWPORTWINDOW_H

 #include <QWindow>
+#include <QTimer>

 #include <string>
 #include <unordered_set>
@@ -305,9 +306,12 @@ private:
    bool  buildHizPipeline();
    bool  buildEdgePipeline();
    void  encodeEdgePass(WGPUCommandEncoder enc, WGPUTextureView surface_view);
-    // setPivotIndicatorVisible moved to ViewportCore — the indicator is drawn
-    // by the shared AxisIndicatorRenderer now, so its visibility (afterglow
-    // included) lives next to the drawing for desktop + web alike.
+    // Show/hide the pivot indicator. hide_after_ms > 0 starts the
+    // single-shot auto-hide timer used by the wheel-zoom afterglow;
+    // drag callers pass 0 and toggle manually on press/release. The
+    // actual gizmo rendering lives in OverlayRenderer — this just
+    // manages the UI-side visibility timer.
+    void  setPivotIndicatorVisible(bool visible, int hide_after_ms = 0);
    // releaseEdgeResources / buildPickPipeline / ensurePickAttachments /
    // releasePickResources moved to ViewportCore (#84-s, #84-t).

@@ -666,10 +670,15 @@ private:
    WGPUBindGroup&      edge_bind_group_;
    bool&               edges_enabled_;

-    // The Qt-coupled viewport overlays (marquee rect, measure lines /
-    // points / labels, highlight triangles) — pipelines + shaders +
-    // buffers + encoders. The viewport builds a OverlayFrame each frame
-    // and asks the renderer to encode each overlay; see OverlayRenderer.h.
+    // Pivot visibility state — the gizmo itself lives in overlays_.
+    // The timer auto-hides the pivot after a wheel-zoom afterglow.
+    bool                pivot_indicator_visible_    = false;
+    QTimer*             pivot_indicator_hide_timer_ = nullptr;
+
+    // All viewport overlays (axis indicator, section gizmos, marquee
+    // rect) — pipelines + shaders + buffers + encoders. The viewport
+    // builds a OverlayFrame each frame and asks the renderer to
+    // encode each overlay; see OverlayRenderer.h.
    OverlayRenderer overlays_;

    // Active measurement tool. setToolMode() / setSelection mutations