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Arbitrary Volume Objects?

Posted: Wed Oct 18, 2017 2:56 am
by jayroth
I have a series of pipe-like cylinders that I would like to treat as if they were actual volumes. I am currently using Raphael Rau's SSS technique which works well when viewing from the outside, but not when the camera is inside the cylinder. I need to confine the volume to the cylinders, otherwise I would just use a typical volume object.

Any ideas?

Re: Arbitrary Volume Objects?

Posted: Wed Oct 18, 2017 5:06 pm
by bepeg4d
Hi jayroth,
you need to parent to the camera a sphere with normals inverted, and the same sss air material applied.
In this way, the camera is inside a ball of air while in the fog. Obviously you need to animate the visibity/rendering of the sphere, because is not necessary when the camera is outside the sss geometry.
ciao beppe

Re: Arbitrary Volume Objects?

Posted: Thu Oct 19, 2017 4:27 pm
by jayroth
Thanks, Beppe, but I am not sure that this solution, which I am familiar with will work in this situation. I need to fill a network of pipes with a volume effect. Imagine the volume object but bound by arbitrary geometry. I have managed to get a decent look from Raphael Rau's recent treatise on SSS in Octane (excellent, BTW!) but when I actually pass through that volume is when the cheat is revealed. I can avoid it with DOF and other tricks, but I was hoping to plus it up a little more...

Re: Arbitrary Volume Objects?

Posted: Thu Oct 19, 2017 4:38 pm
by bepeg4d
Hi jayroth,
difficult to say without screenshots, do you mind to share some?
ciao beppe

Re: Arbitrary Volume Objects?

Posted: Thu Oct 19, 2017 7:59 pm
by jayroth
I will, but I am at work right now :D