trailcode · trailcode · Jul 23, 2026 · Jul 21, 2026 · Jul 21, 2026 · Jul 21, 2026
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -7,6 +7,17 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+
+- WASM (OCCT 7.9.3): stop forcing a near-white AIS `SetColor` after every material apply. That OCCT 8 GLES workaround had been running on all Emscripten builds and made steel, gold, and other presets look identical (glass still showed transparency).
+- WASM: clear AIS `OwnColor` when applying a Shape List material so presets are not stuck on a forced color. Prefer the **OCCT 7.9.3** wasm kit — OCCT 8.x GLES still has known shading regressions (`docs/building-occt.md`).
+
+### Cross-section
+
+- Added a temporary **Shape cross-section** preview tool for selected solids. Entering the tool with solids already selected updates the preview immediately; changing the selection while in the tool also updates it. Options choose a shared local **XY**, **XZ**, or **YZ** plane (first-selected axes, selection-bbox center), **Invert normal** (flips the annotation arrow and positive-offset direction while keeping the plane in place), **Hide back side** (on by default; display-only AIS clip opposite the yellow arrow), a bounding-box **Offset** slider (Ctrl+click to type; auto-updates preview) in project units, and **Clip** (half-space cut: keeps the positive-normal side, deletes the originals, adds clipped replacements; undoable). A translucent yellow plane and normal arrow annotate the cut. Solids the plane misses are skipped; the preview clears only if nothing in the selection is cut.
+- Desktop preview sections multiple selected solids in parallel (worker pool); WASM remains single-threaded for the per-solid pool. Bounding-box culling skips solids that cannot meet the plane. Offset/plane dragging updates the yellow plane immediately and runs section wires asynchronously (cancel + latest-pending) so the Options slider stays responsive.
+- Shapes now carry a bbox-centered local frame that follows baked move/rotate/scale transforms and persists in project JSON and shape undo records.
+
 ### Shape List
 
 - **Shape List** is a hierarchical outliner: organizational **groups**, expand/collapse, drag-and-drop reparent, **Group** / **New group** / **Ungroup**, cascade delete, and Ctrl+click multi-select. Click a group (including empty) to set the **current group**; new primitives/extrudes/revolves are added there. Drop on empty space below the list to move a node to the document root. Group visibility hides the subtree. **Hide all** no longer clears per-shape visibility flags. Boolean results inherit a shared parent when inputs share one. STEP import preserves XCAF assembly groups (unless **Union shapes**).

diff --git a/agents/conventions/occt-wasm-dual-version.md b/agents/conventions/occt-wasm-dual-version.md
@@ -10,6 +10,8 @@
 | WASM (Emscripten) | **7.9.3** (`V7_9_3`) recommended    | `scripts/build-occt-793-wasm.ps1`          |
 | WASM (compare)    | 8.0.0.p1 (`V8_0_0_p1`) experimental | Shading regressions; not for demos/release |
 
+Do **not** apply OCCT 8 GLES workarounds unconditionally under `__EMSCRIPTEN__`. Example: `Occt_view::refresh_shape_shading_` must not force a fixed AIS `SetColor` on 7.9.3 (washes out material presets). Gate with `OCC_VERSION_HEX >= 0x080000`, and when a color is required on OCCT 8 prefer the material's own color.
+
 Details: [docs/building-occt.md](../../docs/building-occt.md), [workflows/local-dev.md](../workflows/local-dev.md).
 
 ## Shared `src/` must compile on both

diff --git a/agents/drafts/issues/active/gh-218-cross-section-tool.md b/agents/drafts/issues/active/gh-218-cross-section-tool.md
@@ -0,0 +1,38 @@
+---
+github_issue: 218
+github_pr: 219
+status: active
+paired_draft: ../prs/active/gh-219-cross-section-tool.md
+---
+
+# Add temporary shape cross-section preview tool
+
+**Suggested labels:** `enhancement`, `ui`, `feature-request`
+
+---
+
+## Title (GitHub)
+
+Add temporary shape cross-section preview tool
+
+## Body (GitHub)
+
+See https://github.com/trailcode/EzyCad/issues/218
+
+### Summary
+
+Interactive **Shape cross-section** tool: shared local plane cut of selected solids with temporary AIS preview; Invert normal, Hide back side, Clip; async wires + desktop parallel pool (no sketch commit in v0).
+
+### Acceptance criteria
+
+- [x] Auto-preview on enter / selection / plane / offset / Invert
+- [x] Hide back side (default on); Clip undoable half-space
+- [x] Bold empty-selection prompt; leave mode or clear selection removes preview
+- [x] Focused tests `Shp_cross_section.*` / `Shp_test.Cross_section*`
+- [x] Docs + CHANGELOG updated
+
+### Related
+
+- PR: https://github.com/trailcode/EzyCad/pull/219
+- Plan: `agents/plans/cross-section-tool.md`
+- Related tracking: #220
diff --git a/agents/drafts/issues/active/gh-220-wasm-alt-drag-multiselect.md b/agents/drafts/issues/active/gh-220-wasm-alt-drag-multiselect.md
@@ -0,0 +1,38 @@
+---
+github_issue: 220
+status: active
+---
+
+# WASM: Alt + LMB drag does not multi-select shapes
+
+**Suggested labels:** `bug`
+
+**Opened:** https://github.com/trailcode/EzyCad/issues/220
+
+---
+
+## Title (GitHub)
+
+WASM: Alt + LMB drag does not multi-select shapes
+
+## Body (GitHub)
+
+See https://github.com/trailcode/EzyCad/issues/220
+
+### Summary
+
+Desktop: **Alt + LMB drag** rubber-band multi-selects shapes via OCCT `AIS_ViewController`. WASM: same gesture does not select multiple shapes.
+
+### Acceptance criteria
+
+- [ ] WASM Alt + LMB drag multi-selects like desktop
+- [ ] Desktop unchanged
+- [ ] Docs note Alt+drag (and any Web caveats)
+- [ ] Plan updated: `agents/plans/wasm-alt-drag-multiselect.md`
+
+### Related
+
+- Issue: https://github.com/trailcode/EzyCad/issues/220
+- Plan: `agents/plans/wasm-alt-drag-multiselect.md` (tracking on PR #219; bug not fixed there)
+- Related: #93 / `gh-93-emscripten-web-hotkeys-followup.md`
+- PR that added tracking: https://github.com/trailcode/EzyCad/pull/219
diff --git a/agents/drafts/prs/active/gh-219-cross-section-tool.md b/agents/drafts/prs/active/gh-219-cross-section-tool.md
@@ -0,0 +1,32 @@
+---
+github_issue: 218
+github_pr: 219
+status: active
+paired_draft: ../issues/active/gh-218-cross-section-tool.md
+---
+
+# PR - Trailcode/cross-section
+
+## Title
+
+Add temporary shape cross-section preview tool
+
+## Summary
+
+- Temporary shape cross-section preview (local XY/XZ/YZ + offset, Invert normal, Hide back side, Clip).
+- Async section wires + desktop parallel pool; WASM serial (see `wasm-multithreading.md`).
+- Shape local frames for plane orientation / persistence.
+
+## Related
+
+- Issue: https://github.com/trailcode/EzyCad/issues/218
+- PR: https://github.com/trailcode/EzyCad/pull/219
+- Branch: `Trailcode/cross-section`
+- Plan: `agents/plans/cross-section-tool.md`
+
+## Test Plan
+
+- [ ] Desktop Release build
+- [ ] `EzyCad_tests --gtest_filter=Shp_cross_section.*:Shp_test.Cross_section*`
+- [ ] Manual enter / selection / plane / offset / Hide back / Clip / Esc
+- [ ] Docs sync checklist
diff --git a/agents/plans/README.md b/agents/plans/README.md
@@ -20,3 +20,5 @@ sketch-mode-shape-faint  (parallel UX: ghost/wire shapes while sketching)
 | [sketch-from-shape-section.md](sketch-from-shape-section.md)     | "sketch from shape", section → editable sketch (end-state; deferred)  |
 | [sketch-mode-shape-faint.md](sketch-mode-shape-faint.md)         | faint/ghost/wireframe shapes in sketch mode, alpha blending solids    |
 | [shape-list-hierarchy-phase3.md](shape-list-hierarchy-phase3.md) | parent transform inheritance, Parts/planes, Boolean history (#214)    |
+| [wasm-multithreading.md](wasm-multithreading.md)                 | WASM/Emscripten pthreads, SharedArrayBuffer, parallel OCCT on web     |
+| [wasm-alt-drag-multiselect.md](wasm-alt-drag-multiselect.md)     | WASM Alt+LMB drag rectangle multi-select broken (#220)                |
diff --git a/agents/plans/cross-section-tool.md b/agents/plans/cross-section-tool.md
@@ -1,5 +1,5 @@
 ---
-status: planning
+status: implemented-v0
 topic: cross-section-tool
 depends_on: shp-origin-orientation
 blocks:
@@ -32,12 +32,12 @@ Fail closed on empty section (status message). No requirement to create a `Sketc
 
 ## Experiment checklist
 
-- [ ] Box mid-plane → rectangle-like wires.
-- [ ] Cylinder mid-plane → circle (or dense curve).
-- [ ] Offset along normal; miss solid → clear failure.
-- [ ] Multi-face / boolean solids: junk edges? duplicates?
-- [ ] Curve types returned (`GeomAbs_*`) — informs sketch import strategy.
-- [ ] WASM vs desktop parity ([occt-wasm-dual-version](../conventions/occt-wasm-dual-version.md)).
+- [x] Box mid-plane -> four line edges (focused unit test).
+- [x] Cylinder mid-plane -> circular edge (focused unit test).
+- [x] Offset along normal; miss solid -> clear failure (focused unit test).
+- [x] Multi-face / boolean solids: junk edges? duplicates? (fused two-box mid-plane returns **8** line edges, not a clean 4-edge rectangle — sketch import will need weld/dedup).
+- [x] Curve types returned (`GeomAbs_*`) -> preview status counts lines, circles, ellipses, B-splines, and other curves.
+- [x] WASM vs desktop parity ([occt-wasm-dual-version](../conventions/occt-wasm-dual-version.md)).
 
 ## Likely touch points
 
@@ -58,3 +58,13 @@ Enough evidence to either:
 Import into `Sketch_edges`; undoable new sketch; script binding (unless useful for tests).
 
 **Related UX:** [sketch-mode-shape-faint.md](sketch-mode-shape-faint.md) — keep the solid visible but faint under section preview.
+
+## Implemented v0 findings
+
+- `Shp` now has a persisted `gp_Ax3` local frame. It defaults to a world-aligned frame at the shape bounding-box center and follows baked move/rotate/scale transforms.
+- `Shp_cross_section` computes one shared cutting plane for the selection with `BRepAlgoAPI_Section` (`Approximation(false)` for exact curve types): orientation from the first selected solid's local axes, origin at the selection bbox center, plus offset. Section edges aggregate into a temporary topmost cyan AIS wire preview, with one translucent yellow plane outline and positive-normal arrow. None of this temporary geometry enters the document or undo history.
+- Preview updates fail closed only when the shared plane misses every selected solid, or a hard OCCT failure occurs. Solids the plane does not intersect are skipped and counted in the status message; the yellow plane annotation remains.
+- The first curve evidence supports line and circle handling. Ellipse/B-spline/other counts are exposed for further manual experiments before sketch import rules are chosen.
+- Boolean solids are not yet sketch-ready: a fused two-box mid-plane yields 8 line edges (likely unmerged/overlapping segments) instead of one 4-edge outer loop.
+- Desktop Release build and focused section tests pass with OCCT 8.0.0. The Emscripten Release build also passes with OCCT 7.9.3.
+- Desktop multi-solid preview sections solids on a `std::thread` worker pool (`for_each_index_` / `section_shapes_on_plane_`); WASM remains single-threaded for that pool. Interactive Options use `request_preview` + `poll`: plane AIS updates immediately; section wires run async with cancel + latest-pending (desktop `std::async`; WASM one solid per poll). WASM pthread enablement is tracked in [wasm-multithreading.md](wasm-multithreading.md).
diff --git a/agents/plans/wasm-alt-drag-multiselect.md b/agents/plans/wasm-alt-drag-multiselect.md
@@ -0,0 +1,73 @@
+---
+status: planned
+topic: wasm-alt-drag-multiselect
+depends_on: []
+blocks: []
+github_issue: 220
+---
+
+# WASM Alt + LMB drag multi-select
+
+**Load only when** the prompt is about WASM/Emscripten Alt+drag, rectangle / rubber-band selection, or multi-select failing on web. Skip otherwise ([token-lean](../conventions/token-lean.md)). Index: [plans/README.md](README.md).
+
+**Issue:** https://github.com/trailcode/EzyCad/issues/220
+
+## Context
+
+On desktop, holding **Alt** and **left-dragging** in the 3D view activates OCCT `AIS_ViewController` rectangle selection (`SelectRectangle` / rubber band) and multi-selects shapes under the box.
+
+On the WASM build the same gesture does **not** multi-select.
+
+EzyCad already maps modifiers into OCCT flags:
+
+- `Occt_view::key_flags_from_glfw_` — `GLFW_MOD_ALT` → `Aspect_VKeyFlags_ALT`
+- Mouse press/release: `PressMouseButton` / `ReleaseMouseButton` with `theMods`
+- Mouse move: `UpdateMousePosition(..., key_flags_from_glfw_window_(), ...)` which polls `glfwGetKey(... LEFT/RIGHT_ALT ...)`
+
+Related input/hotkey tracking: [#93](https://github.com/trailcode/EzyCad/issues/93), draft `agents/drafts/issues/active/gh-93-emscripten-web-hotkeys-followup.md`. OCCT desktop vs wasm kit: [occt-wasm-dual-version](../conventions/occt-wasm-dual-version.md).
+
+## Goal
+
+Make **Alt + LMB drag** multi-select on WASM match desktop, without changing desktop gesture mapping or selection schemes.
+
+## Likely causes (investigate in order)
+
+1. **Alt not present on pointer events under Emscripten/GLFW** — browser menu focus, `preventDefault`, or incomplete `mods` on `glfwSetMouseButtonCallback`.
+2. **`glfwGetKey(ALT)` false during drag** — rubber-band gesture needs Alt on move updates (`key_flags_from_glfw_window_`), not only on button press.
+3. **ImGui / focus** — canvas loses keyboard focus when Alt is pressed; Alt never reaches GLFW.
+4. **OCCT 7.9.3 wasm kit** — confirm default `MouseGestureMap` still binds Alt+LMB to select-rectangle (unlikely difference, but verify if input looks correct).
+
+## Approach
+
+### Phase 0 — reproduce and instrument
+
+- [ ] Confirm desktop Alt+LMB rubber band still works.
+- [ ] On WASM, log (temporary) `mods` on LMB press/release and Alt from `key_flags_from_glfw_window_` during drag.
+- [ ] Note browser (Chrome/Firefox/Edge) and whether the OS/browser steals Alt.
+
+### Phase 1 — fix input path
+
+- [ ] Ensure Alt is forwarded for press, move, and release while the gesture is active (Emscripten/GLFW and/or synthetic modifier from `event.altKey` if GLFW is incomplete).
+- [ ] Avoid focusing browser chrome on Alt when the canvas has focus (as far as the platform allows).
+- [ ] Keep `GUI::on_mouse_button` / sketch `mods == 0` click paths unchanged for unmodified LMB.
+
+### Phase 2 — docs and parity
+
+- [ ] Document Alt+drag multi-select in `docs/usage.md` and/or `docs/usage-occt-view.md`; call out any remaining Web limitation.
+- [ ] Manual check: Ctrl+click multi-select still works on WASM if it already does; Alt+drag matches desktop.
+- [ ] Close #220 when done; update this plan status.
+
+## Out of scope
+
+- WASM pthreads / parallel OCCT ([wasm-multithreading.md](wasm-multithreading.md)).
+- Broader #93 hotkey parity beyond what this gesture needs.
+- Changing default OCCT mouse gesture map on desktop.
+
+## Related code
+
+| Area                         | Path                                      |
+| ---------------------------- | ----------------------------------------- |
+| Modifier → OCCT flags        | `src/gui_occt_view.cpp` (`key_flags_*`)   |
+| Mouse → view controller      | `src/gui_occt_view.cpp` (`on_mouse_*`)    |
+| GLFW → GUI                   | `src/main.cpp`, `src/gui.cpp`             |
+| Draft                        | `agents/drafts/issues/active/gh-220-*.md` |