From BlenderWiki
Spot Volumetric Effects
Spot lights also can produce “volumetric” effects. See this page for more information about what it means.
- Halo
- The Halo button allows a Spot lamp to have a volumetric effect applied to it. This button must be active if the volumetric effect is to be visible. Note that if you are using buffered shadows, you have extra options described in the “Spot Buffered Shadows” page.
- HaloInt
- The HaloInt (“Halo Intensity”) slider controls how intense/dense the volumetric effect is, that is generated from the light source. The HaloInt value has a range of between 0.0 and 5.0 – by default, this value is ignored, as the Halo button is not active. To make HaloInt have an effect, make sure the Halo button is active. The lower the value of the HaloInt slider the less visible the volumetric effect is, while higher HaloInt values give a much more noticeable and dense volumetric effect.
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| Volumetric halo examples for various HaloInt values. | |
- Blender only simulates volumetric lighting in Spot lamps when using its internal renderer. This can lead to some strange results for certain combinations of settings for light’s Energy and HaloInt.
- For example having a Spot light with null or very low light Energy settings but a very high HaloInt setting can result in a dark/black halo, which would not happen in the real world. Just be aware of this possibility when using halos with the internal renderer.
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Note
The halo effect can be greatly enhanced when using buffered shadows: when the Halo Step is not null, they can create “volumetric shadows”. See the page about Spot buffered shadows for more information.
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See Also
