View Full Version : caustics and dielectric material

08 August 2004, 12:00 AM
I created a simple scene with a floor a sphere and a spot light. If I create maya material and turn on caustics I can see it well and it redners very fast, as soon as I create dielectric material it slows down the render and caustics doesn't show up.

Also, it looks like the 6.01 links the lights so you don't have to do it. Is it right or Iam wrong?

08 August 2004, 12:06 AM
also I noticed if you don't have any transparent objects in the scene and still have caustics on( even with only maya shaders) the render will be extrimely slow. As soon as you add transparent object it renders fast.

08 August 2004, 03:14 AM
Are you adding a dielectric photon shader as well?

08 August 2004, 05:04 PM
SO that is the trick that I have to do? Is it possible you can point me somehwere where I can learn how to make this shading network?

Than you!

08 August 2004, 02:57 AM
well...what you can do is
-assign a material to your object.
-go to the shading group node of the material.
-From there you assign a dielectric material to the mental ray material slot.
-After that you assign a dielectric photon material to the photon node. These attributes should be the same as what you have set up in the dielectric material.
- You can choose a different colour if you want to have caustics generated from green glass.
-be sure to adjust your raytrace values otherwise you wont generate proper reflections/refractions.
There is information that will explain in more detail, but this will get you in the right direction.

See the pic for details

08 August 2004, 10:07 PM
Thank you very much!

Do you by anychance know how to apply bumpmap to dielectric material.
If it takest oo much time to explain then can you please tell me where did you learn about all this stuff. It is very hard to find any documentation on mental ray shaders.

08 August 2004, 04:59 AM
this link should help:



08 August 2004, 04:32 PM
Also check out francecaluce awsome bump combiner! It's a much simpler way to get nice bumps with mr materials. Check out this thread HERE ( on how to use it.

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