Apply a curated animation preset to an already-rigged 3D model (retargeting). Pass the rigged GLB in `model` (URL or base64) and a `preset_id` from the animation presets list (see the spritesheet animation-presets endpoint) — only presets that expose a `clip_url` can be applied to a 3D model. The model must have a humanoid-template rig (rig it with rig_type humanoid_template or humanoid_template_hands). Synchronous: returns one retargeted animation — a standalone animation-only GLB in `glb_url` plus an mp4 `preview_url` — in the same `animations` envelope as the animate endpoint. crop_loop trims the clip to its seamlessly-looping span (omit to follow the preset's own loop flag); in_place removes net travel so the character moves on the spot, as game-engine locomotion expects (omit to follow crop_loop). Credits are charged only on success. Requires an API key (user scope).