Design a 3D game fighter ship with a headless Blender Python script

u/MasterMind-Apps gave the same long brief to separate Claude Code sessions, one on Opus 5.5 and one on Fable 5.2, both at high effort. The agent had to design an original player ship for a top-down bullet-hell game using only a Python script run in headless Blender: no downloaded models or textures, under 20,000 triangles, at most six materials, named moving parts, and baked idle and banking animations exported as a GLB. It had to render six views, look at its own renders at least three times and fix what was wrong, then write a short report on time, triangles and fix rounds. A Sonnet session helped write the brief.

The poster judged Fable's ship clearly better, with more detail and a pilot under the canopy, at fewer triangles, but felt Opus reached about 80% of the quality for 38% of the cost. Both picked the same white, orange and cyan look unprompted. A third run had Opus build the first draft and Fable do the fix rounds in the same session: about 14 minutes, 13.8k triangles and $4.02 ($1.38 Opus, $2.64 Fable). Fable added small parts but kept Opus's outline.

The poster calls it one data point, not a benchmark. A commenter says Opus at max effort is much stronger for 3D work than lower effort levels. Blender must be installed and on the path or the agent told where it is, and the poster warns complex models eat usage limits quickly.