caustic lights

[Foremancr]

Does anyone know how to generate the caustics where lights are shining through windows and you see the beams of lights itself. This is also used for underwater scenes whereby the lights changes as time change.

[dcooleymp]

you need to add fog to the light and have raytrace shadows on. This way, any object that would create a shadow on the floor will now cast a shadow inside the fog. If you want just streaks of light, as if it is shadowed through the atmosphere, or some distant tree branch, I would suggest a color map on the light itself. this will create a shadow based on the color instead of any object that may be in the scene.

Good luck!