Closes #7691: Enable bim.measure_tool in edit mode

Register Shift+M in the Mesh keymap so the measure tool can be
invoked while in EDIT_MESH mode without requiring the Explore
workspace tool. Append measure controls (type selector + clear
button) to VIEW3D_HT_tool_header so they are visible in edit mode.

Guard the object deselect in hotkey_S_M to OBJECT mode only, since
deselecting objects has no meaning in edit mode.

Fix snapping: obj.ray_cast() has no valid BVH tree for the active
edit-mode mesh, so vertex/edge snapping was silently failing.
Replace with a BMesh proximity pass via bmesh.from_edit_mesh() when
context.mode == "EDIT_MESH".

Generated with the assistance of an AI coding tool.

src/bonsai/bonsai/bim/module/project/__init__.py

@@ -124,8 +124,16 @@ def register():
         kmi.properties.should_save_as = False
         addon_keymaps.append((km, kmi))
 
+        km = wm.keyconfigs.addon.keymaps.new(name="Mesh", space_type="VIEW_3D")
+        kmi = km.keymap_items.new("bim.explore_hotkey", "M", "PRESS", shift=True)
+        kmi.properties.hotkey = "S_M"
+        addon_keymaps.append((km, kmi))
+
+    bpy.types.VIEW3D_HT_tool_header.append(workspace.draw_measure_tool_header)
+
 
 def unregister():
+    bpy.types.VIEW3D_HT_tool_header.remove(workspace.draw_measure_tool_header)
     if not bpy.app.background:
         bpy.utils.unregister_tool(workspace.ExploreTool)
     del bpy.types.Scene.BIMProjectProperties

src/bonsai/bonsai/bim/module/project/workspace.py

@@ -125,8 +125,9 @@ class ExploreHotkey(bpy.types.Operator):
             bpy.ops.bim.enable_culling("INVOKE_DEFAULT")
 
     def hotkey_S_M(self):
-        for obj in tool.Blender.get_selected_objects():
-            obj.select_set(False)
+        if bpy.context.mode == "OBJECT":
+            for obj in tool.Blender.get_selected_objects():
+                obj.select_set(False)
         measure_type = tool.Project.get_measure_tool_settings().measurement_type
         if measure_type == "FACE_AREA":
             bpy.ops.bim.measure_face_area_tool("INVOKE_DEFAULT")
@@ -158,3 +159,19 @@ class ExploreHotkey(bpy.types.Operator):
 
     def hotkey_A_H(self) -> None:
         bpy.ops.bim.hide_queried_linked_element(unhide_all=True)
+
+
+def draw_measure_tool_header(self, context: bpy.types.Context) -> None:
+    if context.mode != "EDIT_MESH":
+        return
+    prop = tool.Project.get_measure_tool_settings()
+    layout = self.layout
+    layout.separator()
+    row = layout.row(align=True)
+    row.label(text="", icon="EVENT_SHIFT")
+    row.label(text="", icon="EVENT_M")
+    op = row.operator("bim.explore_hotkey", text="Measure Tool", icon="CON_DISTLIMIT")
+    op.hotkey = "S_M"
+    row = layout.row(align=True)
+    row.prop(prop, "measurement_type", text="Measure Type", expand=True, icon_only=True, emboss=True)
+    row.operator("bim.clear_measurement", text="", icon="X")

src/bonsai/bonsai/tool/snap.py

@@ -419,6 +419,16 @@ class Snap(bonsai.core.tool.Snap):
                                     closest_snap.append(point)
                             detected_snaps = closest_snap
 
+        # Edit mode: obj.ray_cast() has no valid BVH for the active edit-mesh, so
+        # use BMesh proximity directly to snap to its current vertices and edges.
+        if context.mode == "EDIT_MESH" and context.edit_object:
+            edit_obj = context.edit_object
+            bm = bmesh.from_edit_mesh(edit_obj.data)
+            snap_points = tool.Raycast.ray_cast_by_proximity(context, event, edit_obj, custom_bmesh=bm.copy())
+            for point in snap_points:
+                point["group"] = "Object"
+                detected_snaps.append(point)
+
         # snap to cut geometry (e.g. in plan view)
         if CutDecorator.installed:
             cut_snaps = []