| name | build-loop-gif |
| description | Expand a short character action such as “打招呼”, “挥手”, “点头”, or “跳一下” into six monotonic key poses on a strict 3×2 spritesheet, assemble a ten-frame ping-pong GIF, and reject or repair discontinuous frames. Use for this project's image-to-GIF prompt planning, Wan image generation, limb-continuity QA, spritesheet validation, and GIF assembly. |
Build Loop GIF
Turn a reference character and a short action into a stable ten-frame looping GIF. Treat prompt planning, image generation, and visual QA as separate stages.
Workflow
- Normalize the short action into one unambiguous movement.
- Identify the smallest set of moving body parts. Explicitly freeze all other limbs, the feet, torso, camera, scale, baseline, clothing, and accessories.
- Resolve left/right anatomically. For a front-facing character, state both the character side and its screen position.
- Plan exactly six single-direction key poses at motion progress
0%, 20%, 40%, 60%, 80%, 100%.
- Do not ask the image model to draw the return arc.
- Render the complete image prompt with the contract in references/prompt-contract.md.
- Generate one strict 3×2 spritesheet with
wan2.7-image-pro.
- Split and remove the green background. Assemble
1,2,3,4,5,6,5,4,3,2, producing ten displayed frames from six generated poses.
- Inspect the contact sheet or GIF. Reject output if any hard check below fails.
Motion planning
For “打招呼” or “挥手”, move only the character's anatomical right arm and hand. In a front view this normally appears on the viewer's left. Keep the left arm down and unchanged in all frames.
Use MiMo-V2.5-Pro only as a text planner. Request JSON with action, moving_part, fixed_parts, and exactly six frames. Validate the response before inserting it into the image prompt. Fall back to a deterministic local plan when the API is missing, unavailable, or malformed.
Do not use MiMo-V2.5-Pro to generate the spritesheet: it outputs text, not images. Use mimo-v2.5 only when image-understanding QA is intentionally added; it can inspect an image but still cannot repair pixels.
Hard visual checks
Reject and regenerate when any condition is true:
- A hand or limb switches side, teleports, crosses the torso unexpectedly, changes length, reverses at an impossible joint angle, or becomes detached.
- An extra or missing hand, arm, leg, accessory, or character appears.
- A non-moving limb changes pose materially.
- Identity, face, clothing, viewpoint, character scale, center, or foot baseline drifts.
- Adjacent outward frames are duplicates or motion does not progress monotonically toward frame 6.
- The transition from the last displayed frame back to frame 1 visibly jumps.
- The sheet is not exactly 3×2, contains borders/text/watermarks, crops the character, or has a nonuniform background.
Never claim a GIF passed by inspecting metadata alone. View the animation or a six-pose contact sheet.
Repair policy
- If all six outward poses are coherent, assemble
1,2,3,4,5,6,5,4,3,2.
- If frames 5–6 are unusable but frames 1–4 are coherent, degrade to
1,2,3,4,3,2 and record a warning.
- If one of frames 1–4 is wrong, regenerate the entire sheet. Do not silently duplicate a neighboring frame because that creates a pause.
- If two generations fail the same limb check, simplify the action amplitude and strengthen moving/fixed-part constraints before retrying.
- Preserve the original generated sheet and record the displayed frame sequence and warnings in job metadata.
