Model Maker

This skill does NOT:

• Render a 3D-looking image — that is image-prompt with a 3D style. This produces geometry you can open in Blender, drop into Unity, or view in AR.
• Rig, animate, or retopologise. What comes back is a static mesh.
• Guarantee a printable model. Watertightness is not checked; see references/limits.md before sending anything to a printer.
• Produce a scene. One prompt is one object.

ROLE

Turn a description into a mesh: write the prompt in the grammar 3D generators actually read, pick the tier, call the runner, report where the file landed and what it cost.

PIPELINE

1. Establish the subject. One object, named concretely. "A low-poly red fox, sitting, tail curled" is a subject. "Something foxlike for a game" is not, and the mesh will show it.

2. Write the prompt. 3D prompting is not image prompting — no camera, no lighting, no lens. Describe form, silhouette, material and scale. Full grammar in references/prompt-grammar.md.

3. Pick the tier. Textured is the default and roughly doubles the cost of bare geometry. Untextured is the right pick when the mesh is going to be re-materialised in the target engine anyway.

4. Estimate + confirm. --cost-only first when the user has not seen a price for this skill before. Every generation is over the $0.10 confirmation threshold, so the runner will ask unless --yes is passed.

5. Execute.

   python3 -m common.runners.cli.model3d \
     --model tripo-v3 \
     --prompt "<the written prompt>" \
     --yes
   

   From a photo, add --image-url ./ref.jpg. The prompt then becomes a hint rather than the whole specification.

6. Report. Print the saved path, the format, and the credits the vendor actually consumed — the runner puts that in the manifest. Say what the file is for: GLB opens in Blender, Unity, Unreal, Godot, and previews natively on iOS and Android.

FLAGS

• --prompt "<text>" — the subject description
• --image-url <path|url> — reference photo; switches to image-to-3D
• --no-texture — bare geometry, cheaper
• --pbr — physically-based materials rather than baked colour
• --face-limit N — polygon budget, when the target engine has one
• --model-version <string> — override the pinned vendor model
• --cost-only / --yes / --check / --output <dir>

CONSTRAINTS

• Needs TRIPO_API_KEY. There is no prompt-only fallback worth having here: a 3D prompt with no mesh is not a deliverable the way an image prompt pasted into Midjourney is. Without the key, say so and stop.

• The download link expires in five minutes. The provider downloads inside the same call that sees the task succeed, so this is handled — but it is why a failed save cannot be retried without regenerating, and regenerating bills again.

• One object per call. Multi-object scenes come back fused and unusable. Generate separately and assemble in the target tool.

• Do not promise print-readiness. See references/limits.md.

REFERENCES (load on demand)

EXAMPLES

See examples/before-after.md — three calibration runs: a game prop from text, a product mesh from a photo, and an untextured base for re-materialising.