3d-print

# 3D Print Skill ## Purpose Generate physically accurate, print-ready 3D models without fabricating dimensions. Always search for real specs first. Never guess measurements. --- ## Workflow ### Step 1 — Search for real specs First, try the local search script: ```bash python3 scripts/search_specs.py "Canon EF 40mm f2.8 lens outer diameter" ``` **If the script returns no concrete millimeter values** (status: `no_instant_answer` or vague text), do NOT stop. Use your own `search_web` tool to query the product's official datasheet, spec page, or Wikipedia. Extract the three key numbers: outer dimension, inner dimension, height. Only proceed to Step 2 once you have real numbers with a source you can cite. All results are cached to `specs_cache.json`. On a cache hit, read the cached result and extract dimensions directly — no re-search needed. ### Step 2 — Decide: preset or custom script **Check if the request matches a preset:** ```bash python3 scripts/generate_model.py --preset cube # 20mm calibration cube python3 scripts/generate_model.py --preset tube # hollow cylinder python3 scripts/generate_model.py --preset bracket # box with through-hole ``` **If the request does NOT match a preset** (e.g. "lens cap with snap-fit tabs", "hook with chamfer", "enclosure with lip", "multi-part assembly"), write a custom Python script on the fly. Use the pattern: ```python import sys sys.path.insert(0, "scripts") import manifold3d as m3d from generate_model import export_3mf, export_stl from pathlib import Path # --- build geometry using manifold3d primitives --- # See references/manifold-examples.md for API reference: # extrusion, revolve, hull, chamfer, loft, snap-fit tabs, threads body = m3d.Manifold.cylinder(height=8.0, radius_low=34.0, circular_segments=64) inner = m3d.Manifold.cylinder(height=8.2, radius_low=33.0, circular_segments=64) result = body - inner.translate([0, 0, -0.1]) # --- export --- out = Path("output") export_3mf(result, out / "lens_cap.3mf", name="lens_cap") export_stl(result, out / "lens_cap.stl") ``` Save the script as `output/<name>_build.py`, run it, then proceed to Step 3. The `export_3mf` and `export_stl` functions from `generate_model.py` handle all file-format details — just call them with the final `Manifold` object. ### Step 3 — Validate the mesh ```bash python3 scripts/validate_mesh.py output/lens_cap.stl ``` **If validation fails**, do NOT just run `--fix` and move on. Read the specific failing checks, trace them back to the geometry construction, and fix the root cause in the build script. Common fixes: - `watertight: FAIL` → a boolean operation left an open edge; add a small Z-offset (e.g. `translate([0, 0, -0.1])`) on the subtracted body so it protrudes past the face - `positive_volume: FAIL` → normals are inverted; the outer shell may be smaller than the inner — check radii - `no_degenerate_faces: FAIL` → a zero-thickness wall from a tight boolean; add at least 0.4mm clearance between faces After fixing, re-run the build script and re-validate. Repeat until all critical checks pass. ### Step 4 — Slice Import `.3mf` into Bambu Studio / PrusaSlicer / Cura. Expected: 0 non-manifold errors, 0 open edges. --- ## Spec Extraction from Cache When `specs_cache.json` already contains an entry for the target part, load and extract dimensions directly instead of re-running search: ```python import json cache = json.load(open("specs_cache.json")) # find the entry whose query matches your part # read result["answer"] or result["abstract"] # parse out numeric values (mm) using your own reasoning # map to: outer_diameter, inner_diameter, height, wall_thickness, etc. ``` Use your reasoning to map prose descriptions ("67.5mm filter thread") to the correct variable in the build script. Do not ask the user to do this mapping manually. --- ## Reference Files | File | Contents | |------|----------| | `references/formats.md` | STL vs 3MF vs STEP — when to use each | | `references/tolerances.md` | FDM accuracy, shrinkage, fit clearances | | `references/design-rules.md` | Manifold rules, wall thickness, overhang limits | | `references/manifold-examples.md` | manifold3d API: extrusion, revolve, hull, chamfer, snap-fit, threads | --- ## Key Constraints - **No fabricated dimensions** — search first, use real numbers with a cited source - **manifold3d for all geometry** — guarantees no non-manifold edges - **Custom script when no preset fits** — `generate_model.py` is a reference, not a limit - **3MF primary output** — ISO/IEC 25422:2025, manifold-safe, Bambu/Prusa/Cura compatible - **Fix root cause on validation failure** — do not rely on `--fix` alone --- ## Common Errors | Error | Cause | Fix | |-------|-------|-----| | "244 non-manifold edges" in Bambu | numpy-stl or bad boolean | Regenerate with `manifold3d` | | Hole too tight | FDM shrinks holes | Add +0.1–0.2mm radius compensation (tolerances.md) | | Part snaps during press fit | No interference margin | 0.1–0.3mm interference (tolerances.md) | | Overhangs fail | >45° without supports | Redesign or add supports in slicer | | `watertight: FAIL` | Subtracted body flush with face | Add Z-offset of 0.1mm on subtracted body | | `search_specs.py` returns empty | DuckDuckGo Instant Answer has no entry | Use `search_web` tool on manufacturer datasheet | --- ## Install ```bash ln -sf /path/to/3d-print-skill ~/.claude/skills/3d-print ``` ## Dependencies ```bash pip install manifold3d trimesh numpy requests ```