psychopath/README.md

Overview

Psychopath is a path tracer, aimed at rendering animations and VFX for film. It is currently still in an early prototyping stage of development.

This project is mostly for fun, but I do hope to eventually get it to a point where it's actually useful. That "for-fun" disclaimer aside, the long-term goals of Psychopath are to support efficient global illumination rendering of scenes that are significantly larger than available RAM and/or that contain procedural elements that need to be generated on-the-fly during rendering.

The approach that Psychopath takes to enable this is to try to access the scene data in as coherent a fashion as possible via breadth-first ray tracing, allowing the cost of HDD access, expensive procedurals, etc. to be amortized over large batches of rays.

Psychopath used to be written in C++ but is now written in Rust. The curious can take a look at the old C++ code-base here.

I occasionally blog about Psychopath's development at psychopath.io.

Building

Building Psychopath is mostly straightforward except for its OpenEXR dependency.

If you have OpenEXR 2.2 installed on your system such that pkg-config can find it, then as long as you have Rust (including Cargo) and a C++ compiler installed, you should be able to build with this command at the repository root:

cargo build --release

However, if you are on an OS that doesn't have pkg-config (e.g. OSX, Windows), or you prefer to do a custom build of OpenEXR, then you will need to download and build OpenEXR yourself and specify the necessary environment variables as documented in the OpenEXR-rs readme.

Once those environment variables are set, then you should be able to build using the same simple cargo command above.

If you have any difficulties, please feel free to file an issue and I'll try to help out as I have time!

Current Features

• Geometry:
  • Triangle meshes (flat shading only)
• Lights:
  • Spherical light sources
  • Rectangular light sources
  • Distant disc light sources (a.k.a. sun lights)
• Motion blur:
  • Camera motion blur
  • Deformation motion blur
  • Transforms and transform motion blur
• Focal blur / DoF
• Spectral rendering (via monte carlo sampling)
• Full hierarchical instancing
• Light Tree sampling for efficient handling of large numbers of lights. (See this thread for an overview of the technique.)

Todo / In-Progress

• Simple material/shading system for surfaces.
• Smooth shaded triangle meshes.
• Direct rendering of Catmull-Clark subdivision surfaces.

PsychoBlend

Included in the repository is an addon for Blender called "PsychoBlend" that lets you used Psychopath for rendering in Blender. However, most Blender features are not yet supported because Psychopath doesn't support them yet.

If you have any trouble getting the addon working, please feel free to file an issue and I'll try to troubleshoot/fix it as I have time!

Features Supported

• Meshes (rendered as flat-shaded triangle meshes)
• Point, area, and sun lamps (exported as sphere, rectangle, and distant disc lights, respectively)
• Focal blur / DoF
• Camera, transform, and deformation motion blur
• Exports dupligroups with full hierarchical instancing
• Limited auto-detection of instanced meshes