Keep the product identical in every AI shot

AI video models redraw the product in every frame. With one photo they guess the hidden sides, and long, soft or printed products drift: wedges turn into blocks, labels melt, cans invent a back. This skill locks the product before any clip is generated and checks every clip after.

Generation runs on varg: REST https://api.varg.ai/v2 (the varg-ai skill) or the MCP server https://mcp.varg.ai/mcp.

1. Write the lock sheet (one per product)

PRODUCT: car seat gap filler, single piece
FIXED GEOMETRY: long thin wedge, ~50 cm long, ~4 cm wide at the top, tapering; seatbelt slot near one end
FIXED SURFACE: black leather-like cover, contrast stitching along the top edge, no logo
ALLOWED MOTION: held, slid into a gap, objects dropped on top; never bent, squeezed or rotated fast
NEVER: boxy, shorter, glossy, another color, a second slot

Separate geometry, surface and motion; never mix an old and a new label in the references (seedance.tv).

2. Build the reference pack

Ref	What	How
@image1 hero	front three-quarter, clean, ≥1080 px	the supplier photo, or gpt_image_2_5 to fix text
@image2 profile	the side that shows true shape and size	nano_banana_2_1 edit of the hero: "the exact same product from the side on white" (5 credits)
@image3 detail	label, logo or material close-up	crop of the real photo
@image4 scale	in a hand or next to a known object	optional

Seedance 2.5 takes up to 9 images, Kling 4 up to 7 references per video, Veo 3.1 Ingredients up to 3. Give each image one role in the prompt: "@image2 only shows the true side profile, not the background" (AuraJZ/ai-product-video).

3. Prompt with a lock block, then one action

Product lock. @image1 is the exact product, front three-quarter view; @image2 is the same product from
the side, showing its true long thin wedge shape (about 50 cm long, 4 cm wide). The product keeps this
exact shape and size: it does not become boxy, does not shorten, does not change color, stitching or the
seatbelt slot. Never re-describe it beyond this.
<scene, one simple action, slow and steady, camera holds still with a slight handheld drift>
Real footage look, no music, no text, no subtitles.

• One action per 4–6 s shot. Late frames drift more: cut before the warp.
• Camera-risk ladder: locked frame → slow push-in → lateral slide → small orbit (15°) → full spin. Climb one step only when the step below holds.
• Banned words: spin, 360, whip, fast zoom, morph, transform, "dramatic zoom into the label".
• Describe the product's color apart from the scene light, or the light recolors it.
• Hands cover the product → it redraws what was covered. Grip a plain face; cut before an occlusion.

4. Check every clip, rerun only what fails

curl -s -X POST https://api.varg.ai/v2/tools/video_analyze/call -H "Authorization: Bearer $VARG_API_KEY" \
  -H "Content-Type: application/json" -d '{"model":"video-analyze","video_url":"CLIP_URL",
  "prompt":"Compare the product in this clip with this description: <lock sheet>. For the first, middle and last second: does shape, size, color, label and every fixed detail match? Answer PASS or FAIL per attribute with the second where it breaks."}'

About 5 credits per clip. FAIL on any fixed attribute → rerun that shot only, with a shorter duration or one step down the camera ladder. Make 3–4 takes of a hero shot and keep the most stable.

5. Put the real product back where text must be exact

For the hero close-up, use the real packshot: a slow push-in on the photo (zoompan) or the generated scene with the packshot overlaid on a static shot:

ffmpeg -loop 1 -i packshot.png -vf "scale=1300:-2,zoompan=z='min(zoom+0.0008,1.12)':d=150:s=1080x1920:fps=30" -t 5 -pix_fmt yuv420p hero.mp4

Curved labels on moving bottles need planar tracking (Mocha) in post; avoid those shots if you can.

Tested

2026-10-28, car seat gap filler. With one photo, seedance_2_5 turned the long wedges into boxy blocks in the reveal shot. With the lock sheet, a side-profile reference made by nano_banana_2_1 (5 credits) and the lock block above, the same shot kept the long wedge shape, the color and the stitching for the whole 6 s (231 credits). Before/after: https://s3.varg.ai/files/194b94d0-58ff-4e8b-91de-4f1959d04013/file_332df2a110a0.mp4

Related skills

varg-unboxing-video and varg-product-hook (shots that need the lock), product-photo-to-video, varg-consistent-characters (people, not products), varg-ai.