diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index 74c4fff..25d2dda 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -5,10 +5,10 @@
   </component>
   <component name="ChangeListManager">
     <list default="true" id="8f0bafd6-58a0-4b20-aa2b-ddc3ba278873" name="Changes" comment="- tech drawing and render improv">
-      <change beforePath="$PROJECT_DIR$/src/fluency/io/project_io.py" beforeDir="false" afterPath="$PROJECT_DIR$/src/fluency/io/project_io.py" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/src/fluency/models/data_model.py" beforeDir="false" afterPath="$PROJECT_DIR$/src/fluency/models/data_model.py" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/src/fluency/technical_drawing.py" beforeDir="false" afterPath="$PROJECT_DIR$/src/fluency/technical_drawing.py" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/src/fluency/ui/technical_drawing_widget.py" beforeDir="false" afterPath="$PROJECT_DIR$/src/fluency/ui/technical_drawing_widget.py" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/WARP.md" beforeDir="false" />
+      <change beforePath="$PROJECT_DIR$/src/fluency/rendering/occ_renderer.py" beforeDir="false" afterPath="$PROJECT_DIR$/src/fluency/rendering/occ_renderer.py" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/src/fluency/ui/main_window.py" beforeDir="false" afterPath="$PROJECT_DIR$/src/fluency/ui/main_window.py" afterDir="false" />
     </list>
     <option name="SHOW_DIALOG" value="false" />
     <option name="HIGHLIGHT_CONFLICTS" value="true" />
@@ -45,48 +45,48 @@
     <option name="hideEmptyMiddlePackages" value="true" />
     <option name="showLibraryContents" value="true" />
   </component>
-  <component name="PropertiesComponent"><![CDATA[{
-  "keyToString": {
-    "Python.2dtest.executor": "Run",
-    "Python.3d_windows.executor": "Run",
-    "Python.Unnamed.executor": "Run",
-    "Python.base.executor": "Run",
-    "Python.data_model.executor": "Run",
-    "Python.debug_dragging.executor": "Run",
-    "Python.draw_widget2d.executor": "Run",
-    "Python.draw_widget_solve.executor": "Run",
-    "Python.fluency.executor": "Run",
-    "Python.fluencyb.executor": "Run",
-    "Python.gl_widget.executor": "Run",
-    "Python.gui_ui.executor": "Run",
-    "Python.kernel.executor": "Run",
-    "Python.main.executor": "Run",
-    "Python.main_window.executor": "Run",
-    "Python.meshtest.executor": "Run",
-    "Python.occ_renderer.executor": "Run",
-    "Python.occ_to_mesh.executor": "Run",
-    "Python.render_backend.executor": "Run",
-    "Python.side_fluency.executor": "Run",
-    "Python.simple_mesh.executor": "Run",
-    "Python.sketch.executor": "Run",
-    "Python.technical_drawing_widget.executor": "Run",
-    "Python.vtk_widget.executor": "Run",
-    "Python.vulkan.executor": "Run",
-    "RunOnceActivity.OpenProjectViewOnStart": "true",
-    "RunOnceActivity.ShowReadmeOnStart": "true",
-    "RunOnceActivity.TerminalTabsStorage.copyFrom.TerminalArrangementManager.252": "true",
-    "RunOnceActivity.git.unshallow": "true",
-    "RunOnceActivity.typescript.service.memoryLimit.init": "true",
-    "codeWithMe.voiceChat.enabledByDefault": "false",
-    "git-widget-placeholder": "feature/occ-migration",
-    "last_opened_file_path": "/Volumes/Data_drive/Programming/fluency/src/fluency",
-    "node.js.detected.package.eslint": "true",
-    "node.js.selected.package.eslint": "(autodetect)",
-    "node.js.selected.package.tslint": "(autodetect)",
-    "nodejs_package_manager_path": "npm",
-    "settings.editor.selected.configurable": "project.propVCSSupport.DirectoryMappings"
+  <component name="PropertiesComponent">{
+  &quot;keyToString&quot;: {
+    &quot;Python.2dtest.executor&quot;: &quot;Run&quot;,
+    &quot;Python.3d_windows.executor&quot;: &quot;Run&quot;,
+    &quot;Python.Unnamed.executor&quot;: &quot;Run&quot;,
+    &quot;Python.base.executor&quot;: &quot;Run&quot;,
+    &quot;Python.data_model.executor&quot;: &quot;Run&quot;,
+    &quot;Python.debug_dragging.executor&quot;: &quot;Run&quot;,
+    &quot;Python.draw_widget2d.executor&quot;: &quot;Run&quot;,
+    &quot;Python.draw_widget_solve.executor&quot;: &quot;Run&quot;,
+    &quot;Python.fluency.executor&quot;: &quot;Run&quot;,
+    &quot;Python.fluencyb.executor&quot;: &quot;Run&quot;,
+    &quot;Python.gl_widget.executor&quot;: &quot;Run&quot;,
+    &quot;Python.gui_ui.executor&quot;: &quot;Run&quot;,
+    &quot;Python.kernel.executor&quot;: &quot;Run&quot;,
+    &quot;Python.main.executor&quot;: &quot;Run&quot;,
+    &quot;Python.main_window.executor&quot;: &quot;Run&quot;,
+    &quot;Python.meshtest.executor&quot;: &quot;Run&quot;,
+    &quot;Python.occ_renderer.executor&quot;: &quot;Run&quot;,
+    &quot;Python.occ_to_mesh.executor&quot;: &quot;Run&quot;,
+    &quot;Python.render_backend.executor&quot;: &quot;Run&quot;,
+    &quot;Python.side_fluency.executor&quot;: &quot;Run&quot;,
+    &quot;Python.simple_mesh.executor&quot;: &quot;Run&quot;,
+    &quot;Python.sketch.executor&quot;: &quot;Run&quot;,
+    &quot;Python.technical_drawing_widget.executor&quot;: &quot;Run&quot;,
+    &quot;Python.vtk_widget.executor&quot;: &quot;Run&quot;,
+    &quot;Python.vulkan.executor&quot;: &quot;Run&quot;,
+    &quot;RunOnceActivity.OpenProjectViewOnStart&quot;: &quot;true&quot;,
+    &quot;RunOnceActivity.ShowReadmeOnStart&quot;: &quot;true&quot;,
+    &quot;RunOnceActivity.TerminalTabsStorage.copyFrom.TerminalArrangementManager.252&quot;: &quot;true&quot;,
+    &quot;RunOnceActivity.git.unshallow&quot;: &quot;true&quot;,
+    &quot;RunOnceActivity.typescript.service.memoryLimit.init&quot;: &quot;true&quot;,
+    &quot;codeWithMe.voiceChat.enabledByDefault&quot;: &quot;false&quot;,
+    &quot;git-widget-placeholder&quot;: &quot;feature/occ-migration&quot;,
+    &quot;last_opened_file_path&quot;: &quot;/Volumes/Data_drive/Programming/fluency/src/fluency&quot;,
+    &quot;node.js.detected.package.eslint&quot;: &quot;true&quot;,
+    &quot;node.js.selected.package.eslint&quot;: &quot;(autodetect)&quot;,
+    &quot;node.js.selected.package.tslint&quot;: &quot;(autodetect)&quot;,
+    &quot;nodejs_package_manager_path&quot;: &quot;npm&quot;,
+    &quot;settings.editor.selected.configurable&quot;: &quot;project.propVCSSupport.DirectoryMappings&quot;
   }
-}]]></component>
+}</component>
   <component name="QodanaReportsService">
     <option name="descriptions">
       <ReportDescription localRun="true" path="/private/var/folders/kg/zm48w_r96yb68mlbzvb9gtq40000gn/T/qodana_output/qodana.sarif.json" reportGuid="5f5b823c-c594-48c5-ae1f-062e30303918" reportId="fluency/qodana/2024-02-04" />
diff --git a/WARP.md b/WARP.md
deleted file mode 100644
index 5f3e288..0000000
--- a/WARP.md
+++ /dev/null
@@ -1,147 +0,0 @@
-# WARP.md
-
-This file provides guidance to WARP (warp.dev) when working with code in this repository.
-
-## Project Overview
-Fluency is a CAD (Computer Aided Design) application built with Python/PySide6 that provides parametric 3D modeling through a timeline-based project system. The application combines 2D sketching with constraint solving, 3D visualization using VTK, and SDF (Signed Distance Function) based mesh generation.
-
-## Common Commands
-
-### Development Environment Setup
-```bash
-# Activate virtual environment (if exists)
-source .venv/bin/activate
-
-# Install dependencies
-pip install -r requirements.txt
-```
-
-### Running the Application
-```bash
-# Run the main application
-python main.py
-
-# Run with debugging
-python -u main.py
-```
-
-### UI Development
-```bash
-# Convert Qt Designer UI file to Python code
-pyside6-uic gui.ui > Gui.py -g python
-```
-
-### Building Executable
-The project uses Nuitka for compilation (configured in `main.py` header):
-```bash
-# Build standalone executable
-nuitka --standalone --plugin-enable=pyside6 --plugin-enable=numpy --macos-create-app-bundle main.py
-```
-
-### Testing
-```bash
-# Run mesh generation test
-python meshtest.py
-```
-
-## Architecture Overview
-
-### Core Components
-
-#### Main Application (`main.py`)
-- **MainWindow**: Central UI controller that manages all widgets and user interactions
-- **Project System**: Hierarchical structure: `Project → Timeline → Component → Sketch/Body`
-- **Signal-based Communication**: Qt signals coordinate between 2D sketching and 3D rendering
-
-#### Project Hierarchy
-```
-Project
-├── Timeline (list of Components)
-└── Component
-    ├── Sketches (dict)
-    ├── Bodies (dict) 
-    └── Connectors (for assembly)
-```
-
-#### Drawing Modules (`drawing_modules/`)
-- **SketchWidget** (`draw_widget_solve.py`): 2D parametric sketching with SolverSpace constraint solving
-- **VTKWidget** (`vtk_widget.py`): 3D visualization and mesh interaction using VTK
-- **PyVistaWidget** (`vysta_widget.py`): Alternative 3D rendering backend
-
-#### Mesh Generation (`mesh_modules/`)
-- **VESTA** (`vesta_mesh.py`): Multi-threaded SDF-to-mesh conversion using marching cubes
-- **Interactor Mesh** (`interactor_mesh.py`): Simplified edge-based meshes for 3D selection
-- **Simple Mesh** (`simple_mesh.py`): Basic mesh utilities
-
-### Data Flow Architecture
-
-#### 2D to 3D Pipeline
-1. **2D Sketching**: User draws in SketchWidget using Qt coordinate system
-2. **Constraint Solving**: SolverSpace resolves geometric constraints
-3. **SDF Generation**: Sketch converted to Signed Distance Functions for 3D operations
-4. **Mesh Generation**: VESTA generates triangle meshes from SDF using marching cubes
-5. **3D Rendering**: VTK displays both solid meshes and interactive edges
-
-#### Signal Flow (from `doc/flow.md`)
-- 2D QPoint → cartesian space → SolverSpace dict → constraint solving → display
-- 3D mesh selection → projection to 2D → sketch widget integration
-
-### Key Classes
-
-#### Core Data Structures
-- **Sketch**: 2D geometric data with origin, normal, points, and constraints
-- **Body**: 3D mesh representation containing SDF objects and interactor meshes  
-- **Component**: Container grouping related sketches and bodies
-- **Interactor**: Simplified edge-based mesh for 3D manipulation
-
-#### Constraint Solving
-The application uses `python_solvespace` for parametric constraint solving:
-- Point-to-point constraints
-- Distance constraints
-- Horizontal/vertical line constraints
-- Point-to-line constraints
-
-### Technology Stack
-- **GUI**: PySide6 (Qt for Python)
-- **3D Graphics**: VTK for rendering, PyVista as alternative
-- **Constraint Solving**: SolverSpace for parametric geometry
-- **Mesh Generation**: SDF library with custom VESTA marching cubes implementation
-- **Scientific Computing**: NumPy for mathematical operations
-
-## Development Workflow
-
-### Adding New Sketch Tools
-1. Add UI button in `gui.ui`
-2. Convert UI: `pyside6-uic gui.ui > Gui.py -g python`  
-3. Connect signal in `MainWindow.__init__()`
-4. Implement tool logic in `SketchWidget`
-
-### Adding New 3D Operations
-1. Extend operation buttons in the Modify group
-2. Implement operation logic using SDF functions
-3. Update Body creation and timeline management
-4. Handle interactor mesh generation for selection
-
-### Debugging Tips
-- Monitor solver results through `SolverSystem` status
-- Use VTK's built-in debugging for rendering issues
-- Check coordinate transformations between 2D sketch and 3D space
-- Verify SDF function outputs before mesh generation
-
-### File Structure
-- `main.py`: Application entry point and main window
-- `Gui.py`: Auto-generated UI code (do not edit directly)
-- `gui.ui`: Qt Designer UI definition file
-- `drawing_modules/`: 2D and 3D rendering widgets
-- `mesh_modules/`: Mesh generation and processing
-- `doc/`: Architecture and command documentation
-
-## Dependencies
-Primary external libraries:
-- `PySide6`: Qt GUI framework
-- `vtk`: 3D visualization toolkit
-- `python-solvespace`: Constraint solving
-- `sdf`: Signed Distance Function operations
-- `numpy`: Numerical computations
-- `scikit-image`: Marching cubes algorithm
-- `names`: Random name generation for sketches
diff --git a/src/fluency/rendering/occ_renderer.py b/src/fluency/rendering/occ_renderer.py
index 6b5f052..61bc92e 100644
--- a/src/fluency/rendering/occ_renderer.py
+++ b/src/fluency/rendering/occ_renderer.py
@@ -1426,14 +1426,18 @@ class OCCRenderer(Renderer):
         ais.SetColor(Quantity_Color(*color, Quantity_TOC_RGB))
         ais.SetDisplayMode(1)  # shaded
         try:
-            ais.SetTransparency(0.65)
+            ais.SetTransparency(0.2)
         except Exception:
             logger.debug("op highlight transparency set failed", exc_info=True)
+        try:
+            ais.SetSelectability(0)
+        except Exception:
+            logger.debug("op highlight selectability set failed", exc_info=True)
         try:
             ais.SetPolygonOffsets(3, 1.0, -0.5)
         except Exception:
             logger.debug("op highlight polygon offset failed", exc_info=True)
-        self._context.Display(ais, True)
+        self._context.Display(ais, False)
         self._op_highlight_ais = ais
         if self._view is not None:
             self._view.Redraw()
diff --git a/src/fluency/ui/main_window.py b/src/fluency/ui/main_window.py
index 22a15d1..876230f 100644
--- a/src/fluency/ui/main_window.py
+++ b/src/fluency/ui/main_window.py
@@ -8,7 +8,7 @@ import os
 from datetime import datetime
 from typing import Any, Callable, Dict, List, Optional, Tuple
 
-from PySide6.QtCore import Qt, Slot, QSize, QSettings
+from PySide6.QtCore import Qt, Slot, QSize, QSettings, QTimer
 from PySide6.QtGui import (
     QAction,
     QColor,
@@ -1383,6 +1383,10 @@ def _replay_body_features(
                         "skipping chamfer"
                     )
                     continue
+            geom = kernel.chamfer(geom, feat.radius, edges=edges)
+            if geom is None:
+                return None
+            continue
 
         if feat.operation in ("array", "pattern"):
             # Pattern needs no sketch — it repeats the running solid.
@@ -1719,9 +1723,12 @@ class MainWindow(QMainWindow):
         # selectable axis / centre / plane from the 3D viewport.
         self._sketch_gizmo_selection: Optional[dict] = None
         self._selected_body: Optional[Body] = None
-        # Track which body we're hiding while an operation-history highlight
-        # is active, so we can restore it when the selection changes.
         self._op_highlight_body_id: Optional[str] = None
+        # Auto-clears the operation-history highlight 1 s after it is shown so
+        # the 3D view returns to its normal, fully-selectable state.
+        self._op_highlight_timer = QTimer(self)
+        self._op_highlight_timer.setSingleShot(True)
+        self._op_highlight_timer.timeout.connect(self._on_op_highlight_timeout)
         # Body-highlight state: when no operation is selected we tint the
         # selected body light-blue; save its original colour to restore later.
         self._body_highlight_id: Optional[str] = None
@@ -2685,6 +2692,12 @@ class MainWindow(QMainWindow):
         """
         if feat.operation in ("cut", "union"):
             return self._compute_tool_shape(body, features, index, feat)
+        # Fillet / chamfer: show a cube covering the corner where the op
+        # was applied, not the whole body.
+        if feat.operation in ("fillet", "chamfer"):
+            shape = self._compute_fillet_bbox_shape(body, features, index, feat)
+            if shape is not None:
+                return shape
         # Default: show the intermediate body after this operation.
         geom = _replay_body_features(
             self._kernel, body, features[: index + 1],
@@ -2748,6 +2761,80 @@ class MainWindow(QMainWindow):
             return None
         return self._kernel._get_shape(tool_geom)
 
+    def _compute_fillet_bbox_shape(
+        self, body: Body, features: List[Feature], index: int, feat: Feature
+    ) -> Optional[Any]:
+        """Return a cube covering where a fillet/chamfer op was applied.
+
+        Replays the body *before* the op, resolves the edges the op
+        touches (the same face-key / fingerprint resolution the replay
+        uses), and returns a box around their bounding volume — a corner
+        marker, not the whole body.  Returns *None* when the op spans
+        the whole body (scope "all") or no edges resolve, so the caller
+        falls back to the intermediate body.
+        """
+        # Scope "all" fillets every edge of the body — a corner cube is
+        # meaningless there, so let the caller show the whole body.
+        if feat.scope == "all":
+            return None
+
+        try:
+            pre_geom = _replay_body_features(
+                self._kernel, body, features[:index],
+                self._through_all_length_for_geometry,
+                component=self._current_component,
+            )
+        except Exception:
+            logger.debug("fillet bbox replay failed", exc_info=True)
+            return None
+        pre = self._kernel._get_shape(pre_geom) if pre_geom is not None else None
+        if pre is None:
+            return None
+
+        # Resolve the fillet/chamfer edges on the pre-op geometry, exactly
+        # as the replay does (FaceKey first, fingerprint fallback).
+        edges: List[Any] = []
+        if feat.face_keys is not None:
+            edges = _resolve_edges_by_face_keys(
+                pre, feat, self._current_component
+            ) or []
+        if not edges:
+            edges = _resolve_edges_by_fingerprint(pre, feat.edge_refs)
+        if not edges:
+            return None
+
+        from OCP.BRep import BRep_Builder
+        from OCP.Bnd import Bnd_Box
+        from OCP.BRepBndLib import BRepBndLib
+        from OCP.BRepPrimAPI import BRepPrimAPI_MakeBox
+        from OCP.TopoDS import TopoDS_Compound
+        from OCP.gp import gp_Pnt
+
+        comp = TopoDS_Compound()
+        builder = BRep_Builder()
+        builder.MakeCompound(comp)
+        for e in edges:
+            builder.Add(comp, e)
+
+        bbox = Bnd_Box()
+        BRepBndLib.AddClose_s(comp, bbox)
+        if bbox.IsVoid():
+            return None
+        xmin, ymin, zmin, xmax, ymax, zmax = bbox.Get()
+
+        # Pad by the fillet radius so the cube comfortably covers the
+        # round/bevel, not just the sharp pre-op edge line(s).
+        pad = float(feat.radius) if feat.radius else 0.0
+        cx, cy, cz = (xmin + xmax) / 2.0, (ymin + ymax) / 2.0, (zmin + zmax) / 2.0
+        w = max(2 * pad, (xmax - xmin) + 2 * pad)
+        h = max(2 * pad, (ymax - ymin) + 2 * pad)
+        d = max(2 * pad, (zmax - zmin) + 2 * pad)
+
+        box = BRepPrimAPI_MakeBox(
+            gp_Pnt(cx - w / 2.0, cy - h / 2.0, cz - d / 2.0), w, h, d
+        )
+        return box.Shape()
+
 
     # ── Body highlight helpers ─────────────────────────────────────────
 
@@ -2777,10 +2864,9 @@ class MainWindow(QMainWindow):
         """Enable 'Del Op' / 'Mirror Op', highlight body or selected op in 3D."""
         item = self._operations_list.currentItem()
 
-        # Restore the body we hid for the previous operation highlight.
-        if self._op_highlight_body_id is not None:
-            self._viewer_3d.set_visibility(self._op_highlight_body_id, True)
-            self._op_highlight_body_id = None
+        # Drop the previous highlight and any pending auto-clear so rapid
+        # re-selection always starts from a clean state.
+        self._op_highlight_timer.stop()
         self._viewer_3d.clear_operation_highlight()
 
         # Restore the previous body colour highlight.
@@ -2805,18 +2891,24 @@ class MainWindow(QMainWindow):
                         body, features, index, feat
                     )
                     if shape is not None:
-                        if body.render_object is not None and body.visible:
-                            self._viewer_3d.set_visibility(
-                                body.render_object, False
-                            )
-                            self._op_highlight_body_id = body.render_object
+                        # Overlay the operation geometry on the still-visible
+                        # body as a hot-pink flash.  The overlay is
+                        # non-selectable, so face/edge/vertex picking keeps
+                        # working while it shows.
                         self._viewer_3d.highlight_operation(shape)
+                        # Auto-clear after 1 s so the view returns to normal
+                        # and the user can work on the body.
+                        self._op_highlight_timer.start(1000)
                 except Exception:
                     logger.debug("op highlight replay failed", exc_info=True)
         else:
             # Base operation (or non-selectable) — highlight body light blue.
             self._highlight_selected_body_light_blue()
 
+    def _on_op_highlight_timeout(self) -> None:
+        """1 s elapsed — drop the operation highlight, restoring the normal view."""
+        self._viewer_3d.clear_operation_highlight()
+
     def _on_mirror_operation(self) -> None:
         """Mirror the body at the selected operation's point in the feature history.