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Next: 1.29 Diagnostic modes.1 Up: 1. Functionality Previous: 1.27 Volume Caustics

# 1.28 Global Illumination in Participating Media2.1

Global illumination in volumes2.1can be used to simulate for example:

- Color bleeding from a colored wall onto gray smoke.
- Multiple light scattering in clouds or other participating media.

Global illumination in participating media is computed much the same way as global illumination on surfaces, except that volume shaders and volume photon shaders are needed.

To change the number of photons used to compute the local intensity of global illumination in volumes, specify a `photonvol accuracy` (and optionally a radius) in the `options` (similar to volume caustics).