---
tags:
- hexgen
- cad
- mesh-generation
---

# hexgen — abc_v1 training data

Training pairs for a decoder that reads a CAD solid and emits a *program* which
compiles to a hexahedral finite-element mesh. Exported from the `hexgen-corpora`
Modal Volume by `modal_app/share_corpus_fn.py`.

| path | contents | size |
|---|---|---:|
| `hexgen_abc_v1/pairs.jsonl` | 133,238 (part, program) training records, one JSON object per line | 2,335 MB |
| `hexgen_abc_v1/holdout_graphs.tar.gz` | 10,179 `.brepgraph.json` — held-out CAD parts, never trained on | 188 MB raw |
| `hexgen_abc_v1/holdout_tess.tar.gz` | 10,179 `.tess.json` — the same parts triangulated, matched by filename | 186 MB raw |
| `hexgen_abc_v1/export_summary.json` | export provenance | 838 B |

A `.brepgraph.json` describes one CAD solid: faces with surface type and
parameters, edges with curves, vertices with positions, and the loops tying them
together. A `.tess.json` is that solid as triangles; the mesh-vs-CAD tools take
the two as a pair.

```bash
uvx hf download hexproj-collab/hexgen-share --repo-type dataset --local-dir ./hexgen-data
cd hexgen-data/hexgen_abc_v1
mkdir -p holdout_graphs holdout_tess
tar xzf holdout_graphs.tar.gz -C holdout_graphs
tar xzf holdout_tess.tar.gz   -C holdout_tess
```

**Do not regenerate the `.tess.json` files.** They were produced by the CAD kernel
on x86 and are frozen; tessellation is not reproducible across architectures, so
rebuilding them on ARM silently changes every downstream score.