| name | trimesh-sim |
| description | Use when driving Trimesh (pure-Python triangular-mesh processing library) via Python scripts — load STL/OBJ/PLY/3MF/GLB, compute volume / area / inertia / convex hull / signed distance / ray casts, repair non-watertight meshes, boolean ops, sample points — through sim runtime one-shot execution. |
trimesh-sim
You are connected to Trimesh via sim-cli.
Trimesh is the standard Python library for triangular-mesh manipulation
(Dawson-Haggerty et al.). Pure Python on top of NumPy/SciPy with optional
acceleration (rtree, embree, mapbox-earcut, scikit-image). Pip-installable
(pip install trimesh).
Scripts are plain .py:
import trimesh
m = trimesh.load('part.stl')
print(m.volume, m.area, m.is_watertight)
if not m.is_watertight:
trimesh.repair.fix_normals(m)
m.fill_holes()
m.export('repaired.stl')
Same subprocess driver mode as PyBaMM / PyMFEM / SfePy.
base/ — always relevant
| Path | What's there |
|---|
base/reference/workflow.md | Load → inspect → repair → analyze → export. |
base/reference/properties.md | Volume, area, inertia, COM, convex hull, bounds. |
base/reference/repair.md | fill_holes, fix_normals, fix_winding, merge_vertices. |
base/reference/operations.md | Boolean (union/diff/intersection), section, slicing, ray casts. |
base/snippets/01_props.py | Verified box + sphere volume/area E2E. |
base/known_issues.md | numpy bool serialization, watertight check, library deps. |
sdk/4/ — Trimesh 4.x
sdk/4/notes.md — version-specific surface notes.
Hard constraints
m.volume only meaningful for watertight meshes. Always check
m.is_watertight first, repair if needed.- Boolean ops require a backend (manifold3d, scad, or blender).
m.intersection(...) raises if none is installed; install
pip install manifold3d for pure-pip.
- JSON-serialize numpy bools / floats explicitly: cast via
bool(...) / float(...) — numpy.bool_ is NOT json-serializable.
- Acceptance != "ran without error". Validate volume/area against
analytical (e.g. box V=LWH, sphere V=4/3πr³) for primitives, or
against a known-good reference STL for complex geometry.
- Print results as JSON on the last stdout line.
Required protocol
- Gather inputs:
- Category A: input mesh path or generation params, expected
property bounds, acceptance criterion.
- Category B: repair tolerance, sampling density, output format.
sim check trimesh.- Write
.py per base/reference/workflow.md.
sim lint script.py.sim run script.py --solver trimesh.- Validate JSON.
