Path Tracing: The Decisions That Matter
A rendering method that simulates light by tracing many random paths through a scene, producing realistic global illumination, reflections and shadows.
Imogen Clarke
The key figures
- Method
- rays bounce through the scene to estimate lighting
- Noise
- fewer samples produce more noise
- Examples
- Blender Cycles, Arnold and RenderMan
- Real time
- GPUs increasingly support path tracing in real time
Why this is worth getting right
Path tracing is the basis of most photorealistic rendering, and understanding its sampling helps balance quality against render time.
Do this, not that
Do
- Increase samples in noisy areas rather than globally
- Use denoisers to reduce render times
- Limit light bounces sensibly
- Optimize lights and materials that cause noise
- Test render times on a representative frame
Don’t
- Maximum samples everywhere
- Caustics and fireflies left unmanaged
- Ignoring render time budgets
- Denoising so strongly detail is lost
When to bring in help
Our advice Bring in help when renders are noisy or render times are too long for deadlines.
Where this comes from
- Blender Foundation — Blender manual: Cycles
- Pixar RenderMan — RenderMan documentation
The figures and practices above come from the sources listed.
Working on something like this?
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Where to go next
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