higgsfield-seedance-vfx

# Higgsfield Seedance VFX — Footage Transformation

This skill is for **editing a clip the user already has**: keep a real subject and the
real camera move, change only what they ask for. It is the video-to-video sibling of
`../higgsfield-seedance/SKILL.md` (the general Seedance director). It **reuses that skill's
grammar verbatim** — the six-slot formula, the Prompt-Craft Laws, the preflight linter —
and adds the transformation layer below. Do not contradict the parent skill; when a shot
needs filter-safety, mode selection, or engine rules, defer to it.

> **This file is the Seedance 2.0 v2v lane.** It stays the right choice when the job needs
> **4K**, `mode=std`, a platform start/end frame, or a `genre` hint. If the plate job is
> running on **Seedance 2.5** — 720p ceiling, up to 30 s, many references — the lane is
> `omni_reference` with the clip attached as a video reference, and its production doctrine
> (source ≥ 4 s, duration = source, the four-batch rule, the performance-inheritance clause)
> lives in `../higgsfield-seedance-2-5/VFX-PIPELINE.md`.

> **This skill is a video-to-video layer on top of `../higgsfield-seedance/SKILL.md`.**
> Every VFX transform is still a Seedance prompt. This skill only changes the *starting
> point*: a real source clip whose subject, performance, and camera move must survive the
> edit. `higgsfield-seedance` § Seedance 2.0 Prompt Modes / Transformation covers the
> *in-clip morph* (a character visibly becoming something else in one take); **this** skill
> covers *preservation-VFX* — lock the real plate, layer the effect in.

## QUICK FACTS
*Routing aids — read the linked sections for the actual rules.*
- The one job: **preserve** everything that makes the source recognizable, **change** only the named element; repeat the fragile guardrail ("face and identity unchanged") at the end [→](#the-core-idea-preserve-then-change-one-thing)
- Run it in **Seedance 2.0, mode std, 4K** — faces, lip-sync and fine detail hold at 4K where they warp at 1080p (`fast` can't do 4K; Cinema Studio caps at 1080p) [→](#resolution-run-it-in-4k)
- `@source` declares the clip as the base (not a style ref); add `@creature`/`@element` only when a real texture keeps getting faked [→](#prompt-anatomy-transform-variant)
- **Three levels** of difficulty: L1 swap the world · L2 change an element in-frame · L3 full handheld cinematic [→](#three-levels)
- Two modes: **add an element** to the plate, or **replace the environment** around a preserved subject [→](#two-transformation-modes)
- **Color matching alone looks pasted-in** — match key direction, bounce, optics/haze, edges/grounding [→](#lighting-integration-the-part-that-makes-or-breaks-it)
- Photoreal creatures need **biological accuracy** (wrinkled, cracked, asymmetric, matte — never smooth/glossy/inflated) + a real contact shadow; a reference image beats a description [→](#photoreal-creature-element-integration)
- Timed zoom synced to a line: anchor it **twice** — semantic (`On the line "…"`) + numeric (`At about Ts`); see `references/dialogue-timing.md` [→](#timed-camera-moves-synced-to-dialogue)
- Prepended-intro budget: `total − intro = surviving window` for the source performance; recompute on every change [→](#duration-discipline)
- Generate the transformed **start frame** first to lock the look before spending video credits; see `references/first-frame.md` [→](#first-start-frame-workflow)
- Output is **plain-text English**, no markdown inside the prompt, easy to copy [→](#output-format)

---

## The core idea: preserve, then change one thing

A transformation prompt has two jobs that pull against each other: **lock** everything that
makes the source recognizable (the person's identity, face, wardrobe, performance, framing,
lens, and camera motion), and **change** only the named element. If you under-specify the
lock, Seedance re-rolls the face or the camera and the edit stops matching the original. So
every prompt states both halves explicitly, and repeats the most fragile guardrail — usually
**"face and identity unchanged"** — at the end of the action.

This is the whole blueprint: real footage goes in, the exact same shot comes back — same
subject, same movement — with only the one requested change applied.

---

## Resolution: run it in 4K

Run everything in **Seedance 2.0, `mode=std`, 4K**. The 4K matters: faces, lip-sync and fine
detail hold at 4K where they warp and fall apart at 1080p — and a footage transform lives or
dies on the preserved face reading as the *same* face. The `4k` resolution enum is
model-verified (`../../specs/model-specs.json` → `seedance_2_0`); the "detail holds at 4K"
observation is a **practitioner claim**, strong but not a spec guarantee.

Two model constraints to respect (from `../higgsfield-seedance/SKILL.md` § Pre-flight Linter):
native 4K is available in **`mode=std` only** — `mode=fast` (Seedance 2.0 Fast) caps at
480p/720p, and inside **Cinema Studio** the model is still capped at 1080p. So a 4K footage
transform must run in std mode, on the standard Seedance 2.0 surface. If the user is on fast
mode or in Cinema Studio and asks for 4K, flag the cap before they generate.

---

## Prompt anatomy (transform variant)

### 1. The `@source` declaration

The source clip is the base, not a style reference. One line:

```
@source: Original <clip name> — <who/what is in it: subject, wardrobe, setting, action>. Preserve
<identity, face, wardrobe, performance, framing, camera and motion> exactly; <what to change —
e.g. enhance only the environment / add the creature on the tower / transform only the right arm>.
```

If a transformation needs a real texture the model keeps faking (an animal's fur, a specific
face), add a **second input** as a texture reference and declare it:

```
@creature: Reference photo of a real <animal> — <fur / face / anatomy notes>. Appearance and
fur/skin texture reference only; ignore the photo's background and lighting, do not use it for the
environment.
```

The user