3d-in-readme

Put a 3D model in GitHub markdown

GitHub renders ASCII STL inside a ```stl fenced code block as an interactive 3D viewer - in READMEs, issues, PRs, discussions, and gists. The readme-3d CLI converts real model files into those blocks.

Workflow

1. Get the model file. Accept .glb, .gltf, .obj, .stl, or .ast. If the user has no model but describes one, generate it first (step 2); otherwise skip to step 3.

2. (Optional) Generate from text. POST to the free three.ws Forge API - no key or account:

   curl -s -X POST https://three.ws/api/v1/ai/text-to-3d \
    -H 'content-type: application/json' \
    -d '{"prompt": "<single object, shape-first description>"}'
   

   If data.status is "done", download data.glb_url. If "pending", poll GET https://three.ws/api/forge?job=<data.job> every 5 s until status is "done" (allow ~2 min). Shape-first prompts work best: silhouette survives the monochrome STL render, textures do not.

3. Convert with a byte budget. Check the target markdown file's current size first, leave headroom under GitHub's 512 KB render limit, and never spend more than ~60% of what remains:

   npx readme-3d model.glb --budget <headroom>kb --name <model_name> -o block.md
   

   Defaults are sensible: 1,500 facets max, Y-up→Z-up correction for GLB/OBJ, coordinates normalized. Add --details when embedding into issues/PR threads so the block collapses.

4. Embed. Insert the contents of block.md where the user wants it (for a README, typically after the intro). Then verify:

   npx readme-3d check README.md
   

   check must print OK. If it reports TOO BIG, reconvert with a smaller --budget - never ship a file over the limit, because GitHub will display the entire file as raw text.

Rules

• ASCII STL only - binary STL in a fence renders as gibberish. The CLI always emits ASCII; never hand-build the block from a downloaded .stl without converting.
• The viewer is monochrome geometry. Warn the user if their model's identity depends on textures or color.
• One hero model beats several small ones; each block costs 45 KB+.
• The block renders on github.com only (README, issues, PRs, discussions, gists) - not on npm, GitLab, or in IDE previews. Mention this if the file is consumed elsewhere.