P2Pref

A C++ plugin for Foundry's Nuke that converts a P (position) pass to a Pref (reference position) pass using an Axis node.

Overview

P2Pref solves a common VFX challenge: projecting textures onto animated or deforming geometry with stable, non-sliding results. By transforming world-space position data (P pass) into reference-space coordinates (Pref pass) using a tracked Axis, you can create stable UV coordinates for texture projection workflows.

Workflow

┌─────────────┐    ┌─────────────┐    ┌─────────────┐    ┌─────────────┐
│   P Pass    │───▶│   P2Pref    │───▶│ PRefToMotion│───▶│  STMap /    │
│ (from 3D)   │    │ + Axis/Loc  │    │             │    │  Projection │
└─────────────┘    └─────────────┘    └─────────────┘    └─────────────┘

P2Pref is designed to work seamlessly with PRefToMotion, which converts the Pref pass into UV/motion vectors for warping textures.

Features

• Converts P pass to Pref pass via matrix transformation
• Works with Nuke's Axis nodes
• Cross-platform support (Linux, macOS, Windows)
• Optimized C++ implementation for production performance

Installation

Pre-compiled Binaries

Pre-compiled plugins are available in the COMPILED folder for supported Nuke versions.

1. Download the appropriate .so (Linux), .dylib (macOS), or .dll (Windows) file
2. Copy to your ~/.nuke directory or any path in your NUKE_PATH
3. Restart Nuke

Building from Source

P2Pref uses CMake with platform-specific configuration files.

Requirements

• CMake 3.10+
• C++11 compatible compiler
• Nuke NDK (included with Nuke installation)

Linux

mkdir build && cd build
cp ../CMakeLists_LINUX.txt CMakeLists.txt
cmake . -DNUKE_VERSION=15.0v1 -DCMAKE_INSTALL_PREFIX=~/.nuke
make && make install

macOS

mkdir build && cd build
cp ../CMakeLists_MAC.txt CMakeLists.txt
cmake . -DNUKE_VERSION=15.0v1 -DCMAKE_INSTALL_PREFIX=~/.nuke
make && make install

Windows

mkdir build && cd build
copy ..\CMakeLists_WIN.txt CMakeLists.txt
cmake . -DNUKE_VERSION=15.0v1 -DCMAKE_INSTALL_PREFIX=%USERPROFILE%\.nuke
cmake --build . --config Release
cmake --install .

See building_step_by_step.txt for detailed build instructions.

Usage

1. Connect your P pass - Feed a render with world-space position data into P2Pref
2. Link an Axis/Locator - Connect a tracked or animated Axis node that represents your projection origin
3. Output Pref - The plugin outputs reference-space coordinates

Basic Node Graph

Read (with P pass)
       │
       ▼
    P2Pref ◀──── Axis (tracked to surface)
       │
       ▼
  PRefToMotion
       │
       ▼
    STMap
       │
       ▼
    Merge

Companion Tools

• PRefToMotion - Converts Pref pass to UV/motion vectors for texture warping
• HOUDINI_NUKE_LOCATOR - Export matrix data from Houdini to Nuke Axis nodes

Compatibility

Platform	Nuke Version	Status
Linux	14.1 - 16.x	✅
macOS	15.0 - 16.x	✅
Windows	14.1 - 16.x	✅

Credits

• Code base inspired by Ivan Busquets' C44Matrix
• Technique inspired by learnings from The Next Level program by Comp Lair, Pedro Andrade

License

This project is provided as-is for the VFX community. Big Thanks goes to Comp Lair for allowing me publishing this tool.

Author

Peter Mercell
petermercell.com

---

Part of the P2Pref → PRefToMotion texture projection pipeline for Nuke.