Guide · Production
Published September 5, 2026 · Updated September 12, 2026

| Symptom | Root cause | Layer |
|---|---|---|
| The same character gets a new face every few segments and slowly turns generic | Diluted description: the face description sits in the middle of long action and technical instructions, and the model falls back to its "attractive face" prior | Layer 1: identity is not first in the sheet prompt, or the sheet is not attached as a reference on every generation |
| Right face, but light and colour temperature jump between shots of the same scene | Baked-in light: the sheet or the plate carries dramatic lighting that every shot inherits and then fights with the storyboard's own lighting | Layer 2: references are not neutral |
| Positions, actions and props do not connect inside one segment; people who are not in the scene walk in | No anchor between shots: continuity is not written, or the storyboard names absent people in negative phrasing ("X exits frame") | Layer 3: continuity |
The sheet exists for recognisability, not mood. Four hard rules:
Known failure: characters in long coats or robes get swallowed by the garment in a 9:16 full-body frame, the coat filling seventy percent of the image and the face shrinking. That is a physical limit of the framing. The fix is a separate half-body sheet that carries the face, at the cost of one more image per character.
In SceneMixer the appearance field produced by script analysis becomes the subject of the sheet prompt directly. Each character gets one 9:16 full-body sheet on white, with face and half-body crops cut automatically, and every later video generation attaches that character's references. Before judging sheet quality, confirm which image model produced it: output size and prior differ a lot between models, and the evidence is the image dimensions and the task record, not a guess.
A scene image is an empty "plate" the video model references. The standard is again neutrality:
Art direction is a project-level setting that feeds scene images, prop images and video prompts, and never the character sheet, otherwise the white-background sheet gets lit like the set.
| Model | Reference inputs | Clip length | Notes | Checked |
|---|---|---|---|---|
| Seedance 2.0 (Volcano Engine Ark) | Text plus image, video and audio references; images can be first frame, last frame or character reference | 4–15 s | Native audio; images up to 30 MB and 300–6000 px per side; one of the video paths in SceneMixer | 2026-09-05, per Ark API docs |
| Wan 3.0 (Alibaba Cloud Model Studio) | Up to 10 reference images, 5 reference videos and 5 reference audios per request; prompt up to 20,000 characters | 2–30 s | 480P / 720P / 1080P; failed generations are not billed; the other video path in SceneMixer | 2026-09-05, per Model Studio API docs |
| Other video models | Most accept image references or first/last frames | Varies | Limits change often; whatever the model, the white sheet plus neutral plate method is the same | 2026-09-05 |
Only verified cells are filled; blanks are blanks, not guesses. What decides consistency is not whether the cap is 9 references or 50, but whether the few you attach are neutral.
When a shot fails, go back to the layer it maps to and fix that layer. "Strengthen the prompt" is not a fix.
How the script itself sets up consistency (one name per location, no more than three or four sets per episode) is in Vertical Short Drama Script Format and Hook Structure. Disclosure and likeness rules are in AI Short Drama Compliance Checklist 2026. To watch the method on a finished series, open the sample dramas: every one shows the cast sheet and each segment's script and video.
Because whatever light and background are baked into the reference is inherited by every shot that character appears in. A sheet shot under cold night light makes daytime scenes drift cold; a prop in the background gets repainted as part of the character. A white background with one directional key light at about 75 degrees only records the structure of the face and carries no scene information, so any shot's lighting can override it.
Diagnose by layer before touching prompts. Different faces across shots is a character-sheet problem: check for flat lighting or a face that is too small in frame. Right face but jumping costume light is the scene plate or the shot lighting fighting each other. Positions and actions that do not connect inside one segment is missing continuity in the storyboard. Each layer has its own fix; rewriting one big prompt makes all three worse.
No. Across dozens of generations the description gets diluted by each segment's action, setting and lighting instructions and the model falls back to a generic attractive face. The stable method is to attach the same character sheet as a reference image to every generation and let the text carry only that segment's action and emotion.
At minimum one 9:16 full-body sheet on white. Lead characters benefit from an additional face crop for close-ups. Characters in long coats or robes tend to be swallowed by the costume in a full-body frame, so a separate half-body sheet that carries the face is worth the extra image.
Appearance text from analysis becomes the sheet's subject; white sheets and neutral plates ride along with every segment you generate.
Sign up freeWatch the same character across shots in the sample dramas before you decide.
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