Metrology: the part still plus overlay dimensions

I2V + timed overlays. A lab clip is not a cinematic CNC bay. It is a part you already measured, plus the numbers you already wrote down. Motion is allowed on the coupon. Invention is not allowed on the callout. If the clip shows a drifted hole or a dimension the model painted into the plate, the video is a drawing of a cousin part.

The still is the contract. The overlay is the claim. They are two jobs.

The part is a photo; the numbers are not

A metrology still is a locked plate: the coupon on the granite, the caliper in frame, the feature the report is about. It is not a paragraph about "a precision-machined aluminium bracket." Paragraphs invent parts. Image-to-video does not get to reopen the print. Frame one is the file you sent.

Seedance 2.5 Image to Video is the still-to-motion row: one approved still in, a continuous clip out, up to 720p, four to thirty seconds, native audio, optional last frame. Image required. Seedance I2V is still the still-to-motion job is the router. This page is only the coupon plus the callouts.

Prompt camera and physics only. A slow push to the bore. A hold on the datum. Do not put "12.40 mm" in the paragraph. Repeating the number is how you invite the model to renegotiate the hole. Type a video model draws has to hold every frame. Witness lines are below that floor. If the number matters, it is already in the PNG, or it is a caption you burn after.

Lock the still the way you would lock a report photo. Then buy seconds.

Overlay the numbers you already measured

Add timed text overlays to a video is add_timestamped_captions: lines you wrote, each with its own start_sec and end_sec, burned onto a standalone file. Nothing is transcribed. You supply every millimetre. The clock is yours.

That is the split. A generate that "also happens to show 12.40" is a generate you cannot edit when the CMM comes back 12.38. An overlay you can retimestamp without a new take. Reports change. Copy lock can be later than picture lock.

Font, size, colour, and position apply to the whole set in a given render, not per line. A different treatment is a second overlay pass. A single persistent badge — a lab name — is a fixed overlay, not a timed sequence.

Do not use this path as auto-captions. If someone is speaking the procedure, add captions to a video transcribes speech. Timed overlays will not listen. The named-job version is timed text overlays are lines you time.

Lock the cut first. If you recut after this pass, every timestamp is attached to the wrong feature.

Motion the coupon, then print the callouts

Once the part still is locked, the generate may move the camera across the feature, write quiet if you do not want a band (native audio is on), and land on a second approved still of the same part. Two different lots is a morph.

It may not clean a burr or square a hole the photo recorded out of round. Those are claims. Keep the feature large in frame. 720p is the ceiling on this endpoint. Thirty seconds in one pass holds a coupon better than stitching four short text-to-video clips around a hole. Then burn the numbers.

Pause the clip. Is the part the coupon you would attach to the report, and are the only numbers on screen numbers you typed? Yes: this job. No, a second hole appeared, or a dimension you never measured: you prompted a scene, or you asked I2V to typeset. Go back to the still. Overlay the real callout.

FAQ

Can I prompt "show 12.40 mm on the bore" into Seedance?

You can. You will get glyphs, or a hole the model adjusted to match the sentence. The number is an overlay. Animate the part. Burn the measurement after picture lock.

Does timed overlay transcribe the inspector?

No. You write and time every line via start_sec / end_sec. For spoken-word subtitles, caption the take. For callouts nobody said, overlay.

Can each dimension have its own colour?

Not in one pass. Size, colour, position, and font are set once for the set. A second treatment is a second burn — not a hidden per-line style here.

Do I need a last frame?

Only when the shot must land on a second approved still of the same part. A hero coupon with a slow push is the usual job. A last frame is control, not a default.