View Full Version : Caustics

02-27-2002, 11:35 PM
How do I create causitcs in 3dsmax4. And I'm talking about manually creating them. I know I can do it with plugins etc. But I would like to know for my own personal reference and tweeking. If some one knows please pm me or just post in here.



02-28-2002, 02:26 AM
The effect for achieving this is a "fake" - but will hopefully achieve what you are after... (Max does not have any caustics as default)

The technique is to apply a "gel" to your lightsource. A "gel" is a manually created texture map that holds the values for the light being cast (with white being the multiplier value of your light and any values below white decreasing the output amount) so basically - a mask for the light.

It's a good idea to have an amount of "over burn" on the light (multiplier of more than 1), or better still - a dedicated (strong) light source (with your gel) for the "caustics" and a seperate light source for the illumination of the scene (try changing the include/exlude list for these lights to get better control) - However, this process is more suited to say the caustics created by water in a pool (bouncing onto a wall or floor).

If you intend for the caustic light to appear in the shadow of an object (say if rendering a glass sphere and you want the classic "spot" burn), then you can apply a map in the Shadow slot of the rollout to create a slight amount of fade/dispersal around the burn area (once again, manually) - and then add to this effect by having a seperate light just to punch in that [b]burn[/i]. You can even drop the mask from the shadow slot into the lights projection (with a high multiplier) to force the illumination... or use an omni with attenuation control.

Bit of a ramble there... sorry if it's muddled,

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