• "make a video in this style" / "apply the pack" / "supplement this footage"
• Assembling generated clips into something with real edit rhythm
• Minting 3D props from a look and getting them back into the video
• Verifying that a finished piece actually matches its reference

• The generation prompt contains zero colour language. Add "Colour: none. Render neutral. Grading is applied afterwards."
• Keep two separate flags:

  --brief

  (what HAPPENS: subject, action, place) and

  --style-steer

  (how it LOOKS). Merging them leaks style words into the scene ("teal" becomes a teal object) and subject words into the grade.
• The model responds to local, checkable rules far better than global ones. "Backgrounds pure black and unlit; subjects blowing toward white" works; "extreme contrast" does not.

"Filmed as ONE continuous take with no hard cuts inside it. It will be cut into 6 pieces of roughly 0.8s in the edit, so the framing, subject and light must keep changing throughout — any 0.8s window has to stand alone as its own shot."

• Re-encode, never stream-copy. Stream copy only cuts on keyframes, which at 0.78s mean shot length rounds every boundary to the nearest GOP — destroying the exact thing the pipeline exists to preserve.
• When supplementing existing footage, use its own shot boundaries. Slicing a base video into contiguous pieces and playing them in order just reassembles the original: every "cut" lands mid-shot and is invisible. Measured, a 20-shot assembly registered only 12 detected cuts. Detect real boundaries and take every Nth so consecutive picks are guaranteed discontinuous. That moved a cut measurement from 1.29s to 0.83s against a 0.78s target.
• Sample shot lengths from the reference's distribution, not from its mean, so the cut inherits rhythm variance instead of flattening to even clips.

• Direct measurement beats a baked LUT when you have the clip: measure it, match its L* CDF, apply zone chroma.

  grade_clip_direct

  reached MAE 1.58 and contrast 34.0 against 34.7.
• Anchor, do not CDF-match, when the clip's histogram is unlike the reference's. Forcing a 68%-black generated clip onto a busy reference histogram lifted the entire background out of black: background preservation fell to 26.0% (CDF) versus 69.0% (anchor), while MAE and contrast both still looked excellent. Default to anchored tone.
• Batch size matters. Grading 48 frames at once OOM-killed the process; 6 is safe.

python mint3d.py --genre <name> --from-stills 4 --retopo --render
python mint3d.py --genre <name> --prompt "a cracked chrome visor" --render

• Generate a clean plate first; do not lift from reference stills. The endpoint's stated input requirement is simple background, single object, object >50% of frame. Reference reels are the opposite of that — collages, wide shots, several subjects, burnt-in graphics — and they produce sculpted noise. Text → single-object plate → mesh costs ~$0.15 extra and is the difference between a usable mesh and a discarded one.
• Multi-view is named per-angle fields, not a list.

  input_image_url

  (front, required), then

  back_image_url

  ,

  left_image_url

  ,

  right_image_url

  ,

  left_front_image_url

  ,

  right_front_image_url

  ,

  top_image_url

  ,

  bottom_image_url

  . There is no

  input_image_urls

  and no

  multi_view

  flag — inventing them degrades every mint to single-view while appearing to work. A wrong angle label is worse than omitting the view, because the model trusts it.
• Address the GLB by key, not by position. The response carries a

  thumbnail

  PNG and a

  model_urls

  block alongside

  model_glb

  ; taking the first URL works only until the keys reorder, and a preview PNG downloads fine — nothing fails until Blender refuses to open it.
• Request PBR maps. Without them the mesh lights like painted cardboard.
• Retopologise if anyone will edit or rig it. Generated meshes are dense and chaotic.
• Render locally to close the loop. Once a turntable is frames, it is footage, and every downstream stage already handles footage — grade it, cut it, screen it as an element, or upload it as a conditioning reference. Use Blender when a binary is on PATH; keep a dependency-light software rasteriser as the default, because a headless GL context is the single most common thing missing from a container and a renderer that only works on a workstation is not part of a pipeline.

• background

  — share of frame below L*10 vs the pack's figure. Compare to the reference, not to the source clip: a generated source at 68% black is blacker than any reference in a 24–55% band, so "preserve the source's blacks" demands the wrong thing and equally excuses a lifted grade.

• chroma_mae

  — per-zone a*/b* error, using the median (matching how the pack's targets were measured; a mean here compares a skew-sensitive statistic to a robust one and reports a definition mismatch as an error).

• contrast

  /

  black_point

  /

  white_point

• banding

  — empty L* histogram bins between occupied ones. Counting total empty bins does not work: a legitimately dark clip has empty highlight bins.

• cadence

  — detected mean shot length vs the reference's.

content_mask

• Trim past the innermost outlier in each outer band, not inward from the edge. Walking in while the current line is hot stops immediately, because the outermost lines are letterbox - flat black, zero edge energy - and the chrome sits inside that at 90-95% of width. The naive version trimmed 1% of frame while the like button stayed in shot.
• Scale to cover, not pad, when portrait source lands in a landscape cut. Padding 9:16 (narrower still after the UI crop) into 16:9 left ~60% of frame as black bars, one shot was nearly an empty rectangle, and it poisoned the background metric because bars are pure black. Covering loses the sides, which is the right trade for centre-framed material.

• Tighten each plate to its alpha bounding box first. That raises coverage from ~4% to 15-35% and hands size control to the caller instead of inheriting whatever fraction of the source frame the element happened to occupy.
• Choose wash vs element by coverage. Diffuse plates (<10% after tightening) work stretched full-frame at low opacity; concentrated ones want to be scaled to 35-70% of frame width and placed.
• Vary placement, scale and rotation per shot from a seeded RNG, so the cut stays reproducible but no two stamped shots share a mark. One plate in one spot every Nth shot reads as a watermark.
• Resolve element geometry in Python, not in ffmpeg expressions:

  pad()

  rejects a negative offset and cannot pad below its input size, so an oversized or off-frame element kills the whole filtergraph.

forge.py

ref

media-rep src

• Project frame rate must be set before import. Resolve locks timeline fps on first timeline creation and conforms the cadence silently. At a sub-second mean shot length that conform is visible.
• The delivered shots are already graded.

  look.cube

  is a normalising LUT for new material and for matching — applying it to the supplied shots double-grades them. Node 1, nothing before it, corrections after.

scripts/HANDOFF-TEMPLATE.md

scripts/blender_prop.py