Volumetric Lights

Volumetric lighting allows effects such as the scattering of light, by fog or smoke, in a scene. Enable the "Scattering" check box on each light. A "Scattering Medium" foreground effect must also be in use (see for more information on how to setup foreground effects).

You may need to adjust the "Medium Density" and "Medium Ambient" parameters of the "Scattering Medium" foreground effect to suit your model. If no volumetric effects are visible, the "Medium Density" is too low. If the rendered image is entirely white, the "Medium Density" is too high.

The default medium is plain white. Optionally, a "density shader" may be set to any solid (not wrapped) color shader, to create the effect of a non-uniform (inhomogeneous) medium. Examples of shaders that can be used are "Blue Marble" and "Solid Clouds". A shader that has been designed explicitly for this purpose is the "Turbulent" shader.

The key points when using volumetric lighting are:

• Remember to turn the "Scattering" parameter of light sources on if you want to see their volumetric effects.

• Use "Medium Density" and "Medium Colour" to define brightness and colour of the lit medium.

• Use a solid color shader set as "Density Shader" for simulation of density variations in the medium.

• Decrease "Error Bound" if image appears spotty outside shadow areas.

• Increase "Min LOD" parameter if areas with volumetric shadows appear spotty.

• Set high "Error Bound" and small "Min LOD" for fast previews.

• Use "Inverse Square Law" for your light's "Fall Off", together with auto exposure, for best results.