Tinsel

A lightweight CPU/GPU path tracer focusing on speed and simplicity. Tinsel was originally designed for rendering out physics based animations where turn around time is more important than generality. It is designed to be easy to set up animation sequences.

Features

• Unbiased uni-directional path tracer
• Disney's principled BRDF with importance sampling of diffuse and specular lobes
• CPU or GPU tracing and shading with a persistent CUDA threads model
• Interactive OpenGL progressive mode
• Explicit area light sampling
• Affine and deformable motion blur
• Gaussian reconstruction filter
• Instanced triangle mesh primitives with affine transformations
• AABB tree with SAH and splitting
• Simple scene description format
• Windows / macOS / Linux support

Example Scene

The scene description in Tinsel is very simple, and loosely based off Arnold's .ass format, here is an example:

# This is a comment

material gold
{
	color 1.0 0.71 0.29
	roughness 0.2
	metallic 1.0	
}

material plaster
{
	color 0.94 0.94 0.94
	roughness 0.5
	specular 0.1
}

material light
{
	emission 5.0 5.0 5.0
}

primitive
{
	type plane
	plane 0 1 0 0
	material plaster
}

primitive
{
	type sphere
	radius 0.5
	material light

	position 0.0 10.0 0.0
	rotation 0.0 0.0 0.0 1.0
	scale 1.0
}

primitive
{
	type mesh
	mesh octopus.obj
	material gold

	position 0.0 0.0 0.0
	rotation 0.0 0.0 0.0 1.0
	scale 2.0
}

Command Line

Image:

tinsel -spp 100 scene.tin output.pfm

Animation (must have ffmpeg in path):

tinsel -spp 100 frame%d.tin output.mp4

Interactive:

tinsel -interactive scene.tin

Todo List

[x] Multiple importance sampling [x] Mesh affine transformation support [ ] Mesh, Disc, Sphere, Plane primitives [ ] Mesh sampling [ ] Multi material meshes [x] SAH and BVH splitting heuristics [ ] Clean up mesh allocations [ ] Command line interface [x] Scene sky parameters [x] Scene camera parameters [ ] Scene include files [x] Scene camera definition [x] Tone mapping [ ] Bloom filter [ ] Blackbody emitters [x] Output formats [x] Triangular noise dither [ ] NLM noise filter [ ] FFmpeg encoding [x] Reconstruction filter [x] Correctness checks [ ] Examples

Supported Platforms

Tinsel ships with makefiles and Visual Studio projects for OSX and Windows respectively. Although not explicitly supported it should be relatively simple to build for Linux.

License

Tinsel is licensed under the ZLib license, see LICENSE.txt.

Author

Miles Macklin - http://mmacklin.com