Diamond - Caustics

[gordonrobb]

Tried a ring in Standalone. Then transferrred the diamond material into LW, and rendered just the diamond.

I'm happy with how they both look, but I would have thought there would have been some cuastics on the base around the diamond.

Anyone got any thoughts on why they don't show? Rendered in PMC with an HDRI background in Standalone, and a bright light in LW>

[kavorka]

what are your material settings?
did you try turning on fake shadows on your spec material?
also, try turning on caustic blur in your kernel settings. Something like .1 to start off.

the term "caustic blur" doesn't sound like it will enable caustics, but I think you need this at a value greater than 0 to have any caustics.

[gordonrobb]

Yeh, I think the caustic blur seems to do what I expected. Caustics are there, they just needed the light pumped up, and some more cooking time.

[panphoto]

Hi Gordon, I'm having almost the opposite problem to you, I seem to have the caustics but can't get your lovely texturing of the diamond! In the hope that we can maybe learn something from each other (this is my first effort with Octane), I've attached my files. You'd you be kind enough to post yours? Thanks, David
OOOPS PS. How do I load LW files?

[gordonrobb]

I would try zipping them up. I'll see what I can sort out when I get home.

[panphoto]

I hope this works!

[gordonrobb]

I see the scene and object file. Are you using an HDRI? If so, is it a standard one and can you point me at it. Want to try to set it up the same as you.

[panphoto]

No HDRI, but you are probably seeing a texture map for the table, but it isn't connected so you can ignore it.

[gordonrobb]

No worries. Got it working.

What you have there aren't caustics. They're reflections. If you turn the spec down all the way on the table, they disappear.. I am rendering g aversion of it now. and will post it and your objects/scene back.

Changes I've made...

Your diamond surface. Main difference is disperssion. Diamonds are about .044% I have also added a gaussian spectrum in the transmission node (as per the LiveDB material).

Rendering wise, DirectLight will not cut it. I have changed it to PMC. Apart form being a physically accurrate kernel, it and path trace are the only ones which will render caustics.

Hope this helps.

[gordonrobb]

Here you go.

I didn't have time to let it cook much.