diff --git a/src/ifcviewer-web/CMakeLists.txt b/src/ifcviewer-web/CMakeLists.txt
index aa3301eb1c..e7dbb004f5 100644
--- a/src/ifcviewer-web/CMakeLists.txt
+++ b/src/ifcviewer-web/CMakeLists.txt
@@ -104,7 +104,7 @@ target_link_options(IfcViewerWeb PRIVATE
     # EMSCRIPTEN_KEEPALIVE alone keeps the symbols in the binary but doesn't
     # add them to Module. ccall lets shell.html pass a JS string (the ?model
     # URL) to load_sidecar_from_url_c without manual heap marshalling.
-    "-sEXPORTED_FUNCTIONS=['_main','_raf_tick_c','_load_sidecar_from_source_c','_clear_scene_c','_ifcv_on_range_done','_ifcv_chunks_resident_c','_ifcv_chunks_total_c','_ifcv_model_count_c','_ifcv_model_resident_c','_ifcv_model_total_c','_ifcv_bytes_total_c','_ifcv_bytes_needed_c','_ifcv_bytes_loaded_c','_view_all_c','_frame_selection_c','_toggle_projection_c','_projection_is_ortho_c','_standard_view_c','_toggle_fly_c','_fly_is_active_c']"
+    "-sEXPORTED_FUNCTIONS=['_main','_raf_tick_c','_load_sidecar_from_source_c','_clear_scene_c','_ifcv_on_range_done','_ifcv_chunks_resident_c','_ifcv_chunks_total_c','_ifcv_model_count_c','_ifcv_model_resident_c','_ifcv_model_total_c','_ifcv_bytes_total_c','_ifcv_bytes_needed_c','_ifcv_bytes_loaded_c','_view_all_c','_frame_selection_c','_toggle_projection_c','_projection_is_ortho_c','_standard_view_c','_toggle_fly_c','_fly_is_active_c','_hide_selected_c','_isolate_selected_c','_show_all_c','_toggle_xray_c','_xray_is_active_c']"
     # ccall: shell.html passes the ?model URL string to load_sidecar_from_url_c.
     # HEAPU8: lets tooling/tests read the wasm heap size (e.g. to verify a large
     # sidecar streams by range instead of loading whole). Standard, zero-cost.
diff --git a/src/ifcviewer-web/main_web.cpp b/src/ifcviewer-web/main_web.cpp
index af6b64ef93..4a0d02bde8 100644
--- a/src/ifcviewer-web/main_web.cpp
+++ b/src/ifcviewer-web/main_web.cpp
@@ -227,6 +227,16 @@ EM_BOOL onKeyDown(int, const EmscriptenKeyboardEvent* e, void* user) {
     // While flying, WASDQE/Shift are held-movement keys, not hotkeys.
     if (app->fly_mode) { if (setFlyKey(app, code, true)) return EM_TRUE; return EM_FALSE; }
     if (e->repeat) return EM_FALSE;
+    const bool alt = e->altKey;
+    // Visibility + X-ray, matching desktop: H hide selected · Shift+H isolate ·
+    // Alt+H show all · Alt+X x-ray.
+    if (!std::strcmp(code, "KeyH")) {
+        if      (alt)   app->core.showAll();
+        else if (shift) app->core.isolateSelected();
+        else            app->core.hideSelected();
+        return EM_TRUE;
+    }
+    if (!std::strcmp(code, "KeyX") && alt) { app->core.toggleXray(); return EM_TRUE; }
     using SV = ViewportCore::StandardView;
     if      (!std::strcmp(code, "Home"))            app->core.viewAll();
     else if (!std::strcmp(code, "KeyF") && !shift)  app->core.frameSelection();
@@ -356,6 +366,13 @@ extern "C" EMSCRIPTEN_KEEPALIVE int fly_is_active_c() {
     return (g_app && g_app->ready && g_app->fly_mode) ? 1 : 0;
 }
 
+// Visibility + X-ray, for the toolbar (same ops as the H/Shift+H/Alt+H/Alt+X keys).
+extern "C" EMSCRIPTEN_KEEPALIVE void hide_selected_c()    { if (g_app && g_app->ready) g_app->core.hideSelected(); }
+extern "C" EMSCRIPTEN_KEEPALIVE void isolate_selected_c() { if (g_app && g_app->ready) g_app->core.isolateSelected(); }
+extern "C" EMSCRIPTEN_KEEPALIVE void show_all_c()         { if (g_app && g_app->ready) g_app->core.showAll(); }
+extern "C" EMSCRIPTEN_KEEPALIVE void toggle_xray_c()      { if (g_app && g_app->ready) g_app->core.toggleXray(); }
+extern "C" EMSCRIPTEN_KEEPALIVE int  xray_is_active_c()   { return (g_app && g_app->ready && g_app->core.xrayActive()) ? 1 : 0; }
+
 // id: 0 Front, 1 Back, 2 Left, 3 Right, 4 Top, 5 Bottom.
 extern "C" EMSCRIPTEN_KEEPALIVE void standard_view_c(int id) {
     if (!g_app || !g_app->ready || id < 0 || id > 5) return;
diff --git a/src/ifcviewer-web/shell.html b/src/ifcviewer-web/shell.html
index 846179b3b7..17ec6f082f 100644
--- a/src/ifcviewer-web/shell.html
+++ b/src/ifcviewer-web/shell.html
@@ -86,6 +86,11 @@
   <button data-view="3" title="Right (Y)">Right</button>
   <button data-view="4" title="Top (Z)">Top</button>
   <button data-view="5" title="Bottom (Shift+Z)">Bottom</button>
+  <span class="sep"></span>
+  <button data-act="hide"    title="Hide selected (H)">Hide</button>
+  <button data-act="isolate" title="Isolate selected (Shift+H)">Isolate</button>
+  <button data-act="showall" title="Show all (Alt+H)">Show all</button>
+  <button data-act="xray"    id="xray-btn" title="X-ray — translucent everything (Alt+X)">X-ray</button>
 </div>
 <div id="status">Starting…</div>
 <script>
@@ -162,6 +167,10 @@
             var fb = document.getElementById('fly-btn');
             if (fb) fb.classList.toggle('active', !!Module._fly_is_active_c());
           }
+          if (Module._xray_is_active_c) {
+            var xb = document.getElementById('xray-btn');
+            if (xb) xb.classList.toggle('active', !!Module._xray_is_active_c());
+          }
           Module._raf_tick_c(Module._app_ptr);
         }
         requestAnimationFrame(shellTick);
@@ -338,6 +347,10 @@
       else if (act === 'focus') Module._frame_selection_c();
       else if (act === 'ortho') { Module._toggle_projection_c(); refreshOrthoLabel(); }
       else if (act === 'fly')   Module._toggle_fly_c();
+      else if (act === 'hide')    Module._hide_selected_c();
+      else if (act === 'isolate') Module._isolate_selected_c();
+      else if (act === 'showall') Module._show_all_c();
+      else if (act === 'xray')    Module._toggle_xray_c();
       else if (view !== null)   Module._standard_view_c(parseInt(view, 10));
     });
   });
diff --git a/src/ifcviewer/ViewportCore.cpp b/src/ifcviewer/ViewportCore.cpp
index 8c307bbf7d..636e206d84 100644
--- a/src/ifcviewer/ViewportCore.cpp
+++ b/src/ifcviewer/ViewportCore.cpp
@@ -4996,6 +4996,49 @@ void ViewportCore::applyPickToSelection(std::uint32_t object_id, bool add, bool
     else             selection_.replace(object_id);
 }
 
+void ViewportCore::hideSelected() {
+    if (selection_.count() == 0) return;
+    for (uint32_t id : selection_.selectionIds()) visibility_.hide(id);
+    const size_t n = selection_.count();
+    selection_.clear();   // hiding deselects, matching the desktop/GL behaviour
+    Log::info().noquote().nospace() << "[wgpu] hid " << n << " selected";
+    host_->requestFrame();
+}
+
+void ViewportCore::isolateSelected() {
+    if (selection_.count() == 0) return;
+    // Hide every object in a VISIBLE model that isn't selected. Model-hidden
+    // objects stay model-hidden (element-level hiding on top is redundant), and
+    // object_id 0 (unpickable) is skipped.
+    const auto& sel_ids = selection_.selectionIds();
+    for (const auto& [mid, m] : models_gpu_) {
+        if (m.hidden) continue;
+        for (const InstanceCpu& inst : m.instances) {
+            if (inst.object_id == 0) continue;
+            if (sel_ids.find(inst.object_id) == sel_ids.end())
+                visibility_.hide(inst.object_id);
+        }
+    }
+    Log::info().noquote().nospace() << "[wgpu] isolated " << selection_.count();
+    host_->requestFrame();
+}
+
+void ViewportCore::showAll() {
+    if (visibility_.hiddenCount() == 0) return;
+    visibility_.clear();
+    Log::info() << "[wgpu] show all";
+    host_->requestFrame();
+}
+
+void ViewportCore::toggleXray() {
+    constexpr float kXrayOnCap = 0.3f;
+    xray_alpha_cap_ = (xray_alpha_cap_ < 1.0f) ? 1.0f : kXrayOnCap;
+    Log::info().noquote().nospace()
+        << "[wgpu] x-ray " << (xray_alpha_cap_ < 1.0f ? "ON" : "OFF")
+        << " (cap=" << xray_alpha_cap_ << ")";
+    host_->requestFrame();
+}
+
 #if defined(__EMSCRIPTEN__)
 void ViewportCore::pickObjectAtAsync(int x_pixels, int y_pixels,
                                      std::function<void(std::uint32_t)> cb) {
diff --git a/src/ifcviewer/ViewportCore.h b/src/ifcviewer/ViewportCore.h
index b09a41378b..95304248f4 100644
--- a/src/ifcviewer/ViewportCore.h
+++ b/src/ifcviewer/ViewportCore.h
@@ -624,6 +624,19 @@ public:
     // Marks selection_ dirty for the next render's flush.
     void applyPickToSelection(std::uint32_t object_id, bool add, bool remove);
 
+    // Visibility + X-ray, shared by desktop (H / Shift+H / Alt+H / Alt+X) and
+    // web. Hidden objects are skipped by the cull and xray_alpha_cap_ is read
+    // by the frame uniform, both per frame — so each call just mutates state and
+    // schedules a frame; no GPU buffers to rebuild.
+    void hideSelected();      // hide the selected objects, then clear selection
+    void isolateSelected();   // hide everything that is NOT selected
+    void showAll();           // clear the hidden set
+    size_t hiddenCount() const { return visibility_.hiddenCount(); }
+    // Global X-ray: translucent everything. Flips the frame uniform's alpha cap;
+    // the cull classifier routes every instance through the transparent pass.
+    void toggleXray();
+    bool xrayActive() const { return xray_alpha_cap_ < 1.0f; }
+
 #if defined(__EMSCRIPTEN__)
     // Async object pick for the web build: encodes the same pick pass as
     // pickObjectAt but reads the staging buffer back via a spontaneous map
diff --git a/src/ifcviewer/ViewportWindow.cpp b/src/ifcviewer/ViewportWindow.cpp
index c43413b622..cc201fdfaa 100644
--- a/src/ifcviewer/ViewportWindow.cpp
+++ b/src/ifcviewer/ViewportWindow.cpp
@@ -1124,36 +1124,11 @@ void ViewportWindow::setSelectedObjectId(uint32_t id) {
     if (isExposed()) requestUpdate();
 }
 
-void ViewportWindow::hideSelectedElements() {
-    if (selection_.count() == 0) return;
-    for (uint32_t id : selection_.selectionIds()) visibility_.hide(id);
-    selection_.clear();
-    if (isExposed()) requestUpdate();
-}
-
-void ViewportWindow::isolateSelectedElements() {
-    if (selection_.count() == 0) return;
-    // Hide every object in a visible model that isn't in the selection.
-    // Model-hidden objects stay model-hidden — element-level hiding on
-    // top of that is redundant and just bloats hidden_ids_.
-    const auto& sel_ids = selection_.selectionIds();
-    for (const auto& [mid, m] : models_gpu_) {
-        if (m.hidden) continue;
-        for (const InstanceCpu& inst : m.instances) {
-            if (inst.object_id == 0) continue;
-            if (sel_ids.find(inst.object_id) == sel_ids.end()) {
-                visibility_.hide(inst.object_id);
-            }
-        }
-    }
-    if (isExposed()) requestUpdate();
-}
-
-void ViewportWindow::showAllElements() {
-    if (visibility_.hiddenCount() == 0) return;
-    visibility_.clear();
-    if (isExposed()) requestUpdate();
-}
+// Visibility ops now live in ViewportCore (shared with web); these stay as thin
+// Qt-facing wrappers for the menu actions.
+void ViewportWindow::hideSelectedElements()    { core_.hideSelected(); }
+void ViewportWindow::isolateSelectedElements() { core_.isolateSelected(); }
+void ViewportWindow::showAllElements()         { core_.showAll(); }
 
 void ViewportWindow::invertElementVisibility() {
     // Compute the new hidden set: every live object_id in a visible model
@@ -1988,53 +1963,13 @@ void ViewportWindow::keyPressEvent(QKeyEvent* event) {
     //   Shift+H  — isolate selected
     //   Alt+H    — show all (clear hidden set)
     //   Shift+F  — enter fly mode (Esc exits)
-    if (key == Qt::Key_H && mods == Qt::AltModifier) {
-        if (visibility_.hiddenCount() == 0) return;
-        visibility_.clear();
-        Log::info() << "[wgpu] show all";
-        requestUpdate();
-        return;
-    }
-    // Alt+X — toggle global X-ray (translucent everything). The frame
-    // uniform `xray_alpha_cap` clamps `fs_main`'s output alpha; the cull
-    // classifier sees `xray_alpha_cap_ < 1` and routes every instance
-    // through the transparent pass so the blend actually fires.
+    // Visibility + X-ray math lives in ViewportCore (shared with web).
+    if (key == Qt::Key_H && mods == Qt::AltModifier) { core_.showAll();        return; }
     if (key == Qt::Key_X && mods == Qt::AltModifier && !event->isAutoRepeat()) {
-        constexpr float kXrayOnCap = 0.3f;
-        xray_alpha_cap_ = (xray_alpha_cap_ < 1.0f) ? 1.0f : kXrayOnCap;
-        Log::info().noquote().nospace()
-            << "[wgpu] x-ray "
-            << (xray_alpha_cap_ < 1.0f ? "ON"  : "OFF")
-            << " (cap=" << xray_alpha_cap_ << ")";
-        requestUpdate();
-        return;
-    }
-    if (key == Qt::Key_H && mods == Qt::ShiftModifier) {
-        if (selection_.count() == 0) return;
-        size_t hidden_now = 0;
-        for (auto& [mid, m] : models_gpu_) {
-            for (const auto& inst : m.instances) {
-                if (selection_.contains(inst.object_id)) continue;
-                if (!visibility_.isHidden(inst.object_id)) {
-                    visibility_.hide(inst.object_id);
-                    ++hidden_now;
-                }
-            }
-        }
-        Log::info().noquote().nospace() << "[wgpu] isolated " << selection_.count()
-                                    << " (hid " << hidden_now << " others)";
-        requestUpdate();
-        return;
-    }
-    if (key == Qt::Key_H && mods == Qt::NoModifier) {
-        if (selection_.count() == 0) return;
-        for (uint32_t id : selection_.selectionIds()) visibility_.hide(id);
-        const size_t n = selection_.count();
-        selection_.clear();   // hiding deselects, matching GL behaviour
-        Log::info().noquote().nospace() << "[wgpu] hid " << n << " selected";
-        requestUpdate();
-        return;
+        core_.toggleXray(); return;
     }
+    if (key == Qt::Key_H && mods == Qt::ShiftModifier) { core_.isolateSelected(); return; }
+    if (key == Qt::Key_H && mods == Qt::NoModifier)    { core_.hideSelected();    return; }
     if (key == Qt::Key_F && mods == Qt::ShiftModifier && !event->isAutoRepeat()) {
         enterFpsMode();
         return;