---
name: "virtual_production_basics"
description: "Plan and prep an LED-volume virtual production shoot: what an LED volume is, the ICVFX pipeline (wall, tracking, render engine, nDisplay), inner vs outer frustum, when VP beats green screen, and a pre-shoot checklist for camera, tracking, and environment readiness. Use when someone asks about virtual production, LED volumes, in-camera VFX, shooting on an LED stage, or planning a shoot that replaces locations or green screen with real-time backgrounds."
metadata: { "includeInPrompt": true }
---

# Virtual Production Basics

## Purpose
Give a team that has never shot on an LED volume a correct working picture of the pipeline, so they can decide whether VP fits the shoot, ask the right questions of the stage, and Show up prepared instead of discovering the constraints at call time. This is the introductory lane: concepts, decision criteria, and a pre-shoot checklist. It does not teach Unreal Engine operation or wall calibration. Those are specialist jobs.

## Workflow

### 1. Decide whether VP fits before anything else
VP shines when the background needs to be photographed, not composited: reflective surfaces (car paint, helmets, glass), night driving, magic-hour looks that would take days on location, scenes where actors need to see and react to the world, and shoots that need fast turnaround with little post. Lean away when the shot list needs direct harsh sunlight, extreme camera-to-wall distance, or heavy post VFX anyway (then the wall is an expensive background). See `references/vp-vs-greenscreen.md` for the full decision grid.

### 2. Understand the three moving parts
- **The wall**: LED panels arranged in a curve (sometimes with a ceiling strip) showing a real-time environment. Fine pixel pitch and shutter-synced refresh rates keep moire and tearing away.
- **The tracking**: an optical (IR cameras like OptiTrack) or inertial system reports the physical camera's position, rotation, and lens data into the render engine with sub-frame latency. Drift here is the fastest way to break the illusion.
- **The engine**: Unreal Engine is the industry standard. Its **nDisplay** system splits the render across a GPU cluster and draws each wall segment from the tracked camera's point of view, so the background shifts with **parallax** (near objects move faster than far ones, exactly like a real location).

### 3. Know the inner/outer frustum split
The wall does not render one image. The **inner frustum** is the perspective-correct slice the camera actually sees: high detail, tracked to the lens. The **outer frustum** is the rest of the wall: lower detail, but it bathes the talent and physical set in the environment's light and feeds reflections. A common fallback: turn the inner frustum green for keying while the outer frustum keeps providing correct interactive light. If someone says "final pixel," they mean the inner frustum image ships as-is with no comp work.

### 4. Front-load the work into prep
The standing VP rule is "previs is production." Blocking, environments, lighting studies, and lens tests happen in the engine before shoot day, because changing a mountain at 2 AM on set is cheap but changing a wall rig is not. Lock the environment states (day/dusk/night variants), test pixel pitch and moire at the actual camera distance, and calibrate the tracked camera and lens encoders for every focal length on the shot list.

### 5. Run the pre-shoot checklist
Work through `references/shoot-day-checklist.md`: tracking health (latency, drift, marker occlusion), genlock/sync between camera shutter and wall refresh, color pipeline agreement between DP and the wall operator, clean plates and charts shot through the wall state, and a named fallback plan per shot (final-pixel vs live-comp vs green-frustum). Confirm who owns each box: DP, VP supervisor, tracking tech, engine operator.

## Output Contract
- A **VP-fit decision**: which shots are final-pixel candidates, which need fallback, and why, in plain language, before any booking.
- A **completed pre-shoot checklist** with an owner per item and a fallback per risky shot.
- From any shoot using this skill: no shoot day spent discovering the wall can't do what the shot list needs. Every constraint was found in prep.

## Operating Rules
1. Every factual claim must be verifiable. Unreal Engine, nDisplay, inner/outer frustum behavior, and tracking approaches are sourced in `references/sources.md`; do not invent specs, panel models, frame rates, or precision figures.
2. Never promise a final-pixel result without the checklist: untracked cameras, uncalibrated lenses, and unsynced shutters make final-pixel a gamble, not a plan.
3. Keep the human in the loop: the DP and the wall operator agree on color and exposure language before the shoot, not after dailies.
4. This skill is basics. Do not author Unreal configs, nDisplay files, or calibration procedures. Point the team at the stage's VP supervisor for those.
5. No em dashes, no ChatGPT-speak. Write like a person explaining a shoot to another person.