mesh-analysis

name	mesh-analysis
description	Analyze STL meshes for 3D printability — checks manifold integrity, wall thickness, overhangs, dimensions, and generates a structured report. Use when asked to validate or inspect an STL file.

Mesh Analysis Skill

Use this skill to analyze STL files for 3D print readiness.

Bundled Script

This skill includes scripts/analyze_mesh.py which performs comprehensive mesh analysis.

Workflow

Step 1: Install Dependencies

This skill requires Python 3 and the trimesh and numpy packages. Before running any scripts, install:

python -m pip install -r "<skill_dir>/requirements.txt"

Important: Package installation can take a few minutes. Use timeout_secs: 300 when running this command via shell.execute.

If installation fails, stop and report to the user that trimesh is required.

Step 2: Run the Analysis

Run the bundled analysis script against an STL file:

python "<skill_dir>/scripts/analyze_mesh.py" "<stl_path>"

For checking fit within a build volume:

python "<skill_dir>/scripts/analyze_mesh.py" "<stl_path>" --build-volume 250x210x220

Step 3: Interpret Results

The script outputs a JSON report:

{
  "file": "design.stl",
  "mesh_integrity": {
    "is_watertight": true,
    "is_manifold": true,
    "has_degenerate_faces": false,
    "euler_number": 2,
    "connected_components": 1
  },
  "dimensions": {
    "bounding_box_mm": {"x": 40.0, "y": 30.0, "z": 20.0},
    "volume_mm3": 18400.0,
    "surface_area_mm2": 5200.0
  },
  "mesh_quality": {
    "triangle_count": 1248,
    "vertex_count": 626,
    "face_area_range_mm2": {"min": 0.5, "max": 12.3}
  },
  "printability": {
    "fits_build_volume": true,
    "build_volume_mm": {"x": 250, "y": 210, "z": 220}
  },
  "issues": [],
  "verdict": "PASS"
}

Step 4: Report Findings

Structure your analysis as:

• Summary: One-line pass/fail verdict
• Mesh Statistics: Triangle count, volume, surface area, bounding box
• Issues Found: Each issue with severity and description
• Recommendations: Actions to fix issues
• Print Readiness: Overall assessment

What to Check

1. Mesh Integrity: Non-manifold edges, inverted normals, degenerate triangles, holes
2. Printability: Thin walls (< 0.8mm), unsupported overhangs, bridging distances
3. Dimensions: Bounding box, fit within build volume, overall volume
4. Geometry Quality: Triangle count, mesh density, face area distribution

Tips

• If the mesh is clean, say so clearly — don't manufacture problems
• Distinguish between issues that WILL cause failure vs. MAY reduce quality
• Be specific about issue locations when possible
• Suggest concrete repair actions (e.g., "increase wall thickness from 0.4mm to 1.2mm")