# Production 3D Notes

## Validation target

The bundled `examples/robot-arm.dwfx` is treated as the production 3D canary.

Expected result:

```text
page kind: w3d-model
meshes: 37
vertices: 32,979
triangles: 49,552
feature edges: 18,075
page diagnostics: 0
```

Run:

```bash
npm run build
npm run validate:production
```

## Fail-closed policy

For eModel sections that declare `.w3d` or `.hsf` geometry, the loader does not silently display a thumbnail if W3D parsing fails. It reports an explicit unsupported page with diagnostics. Thumbnail fallback is allowed only when no 3D stream is declared.

## Memory policy

The 3D renderer uploads each decoded mesh once into GPU buffers and keeps a bounded scene cache:

```ts
new DwfViewer(container, {
  maxGpuCacheBytes: 160 * 1024 * 1024,
  maxCachedScenes: 2,
  maxDevicePixelRatio: 2,
  maxCanvasPixels: 16_777_216
});
```

## Browser deployment

Serve the WASM file with `application/wasm`. The Cloudflare Pages demo writes `_headers` during `npm run build:demo` to set the MIME type and cache headers.

## Unsupported semantics

Unsupported historical HSF opcodes, advanced CAD display-list behavior, and full Design Review parity are tracked as incremental parser work. The rendering contract is: exact-enough supported semantics are displayed, unsupported semantics are diagnosed, and known-failing 3D geometry is not hidden by image fallback.

## 2D production rendering update

Version 0.6.0 adds WebGL acceleration for XPS/DWFx vector geometry and keeps text/images in a Canvas overlay. This avoids CPU redraw bottlenecks when zooming dense sheets and keeps GPU memory bounded through scene cache limits. Embedded ODTTF fonts are deobfuscated and loaded through FontFace where supported, producing CAD-like text weights in the demo.