Help with some glass material

[nikolatesla20]

Help!

I have here a glass cube, with a plane underneath it.

The glass is a specular material, IOR 1.51, transparent, with RGB absorb of white (all sliders all the way down so it doesn't absorb)

I am using an HDRI EXR environment map, "Campus_probe"

Wondering if anyone can help me get rid of the artifacts circled in the picture - not sure what is causing them. They seem to be there even with other EXR maps.

I'm using Blender 2.45 with Indigo 1.0.9 and blendigo that matches (1.0.9)

The cube has a bevel modifier on it to create the bevels. The behavior is the same whether I "apply" the modifier or not.

Thanks!

-niko

[zsouthboy]

Those look like reflections of high-frequency data in the .exr map (trees, perhaps?)

[nikolatesla20]

I thought perhaps they were, but it does it in two different EXR maps.

I've found a studio lighting EXR map so I'm going to try that and see if it gets rid of it.

-niko

[nikolatesla20]

Hm no it seems to still be there. I wonder if it is some other settings I need to make for Indigo.

I've attached the IGS file, you can use any EXR map and it seems to do the same thing..

Also attached is EXR map for the studio..



-niko

[OnoSendai]

I think it's just noise, from light bouncing around inside your object.

[Borgleader]

Well it seems to be "selective" since it appears more in some areas. But it could also be a combination of both.

[CTZn]

As Ono said; it's called TIR (total internal reflection). It's a physical effect not an artifact. Try without bidir, the noise should reduce faster.

[nikolatesla20]

Will I still get proper caustics without bdir though?

THanks for your help guys.

-niko

[CTZn]

I bet you will.

This effect is caused by the reflections inside the glass panels, when light is trapped within due to reflection angle being to low for exitance, a bit like when to mirrors are facing.