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Volume IOR

Posted: Fri Dec 13, 2019 4:52 pm
by wasd
We can't really have any IOR on volumes, right? It's only surface which can have IOR?

Re: Volume IOR

Posted: Fri Dec 13, 2019 4:57 pm
by Fox
Hetero volume has ior.

Re: Volume IOR

Posted: Fri Dec 13, 2019 5:01 pm
by Dade
wasd wrote: Fri Dec 13, 2019 4:52 pm We can't really have any IOR on volumes, right? It's only surface which can have IOR?
All volumes have IORs however it is used (i.e. there is refraction) only when the surface between them is glass.

Re: Volume IOR

Posted: Fri Dec 13, 2019 5:03 pm
by B.Y.O.B.
It is useful (and correct) to have IOR setting on volumes, because then LuxCore can calculate the intermediate IORs of the surfaces around the volumes automatically. E.g. the IOR for a surface that is a water-glass transition.

Re: Volume IOR

Posted: Fri Dec 13, 2019 5:07 pm
by wasd
Dade wrote: Fri Dec 13, 2019 5:01 pm
wasd wrote: Fri Dec 13, 2019 4:52 pm We can't really have any IOR on volumes, right? It's only surface which can have IOR?
All volumes have IORs however it is used (i.e. there is refraction) only when the surface between them is glass.
Is there the way to simulate hot air for example?

Re: Volume IOR

Posted: Fri Dec 13, 2019 7:04 pm
by Dade
wasd wrote: Fri Dec 13, 2019 5:07 pm Is there the way to simulate hot air for example?
IOR is constant over all the volume so it is not possible to simulate hot air for desert-like optical illusions; they are the result of different air temperature => different density => different refraction. It would require to write same ad hoc code to do ray marching over an heterogeneous IOR volume. Not easy to do.

Re: Volume IOR

Posted: Fri Dec 13, 2019 7:55 pm
by wasd
Dade wrote: Fri Dec 13, 2019 7:04 pm
wasd wrote: Fri Dec 13, 2019 5:07 pm Is there the way to simulate hot air for example?
IOR is constant over all the volume so it is not possible to simulate hot air for desert-like optical illusions; they are the result of different air temperature => different density => different refraction. It would require to write same ad hoc code to do ray marching over an heterogeneous IOR volume. Not easy to do.
I see. Then, is it possible to make something like Cycles Refraction node?
https://docs.blender.org/manual/en/dev/ ... ction.html
Here's an example https://youtu.be/3UacrK-wngw

Re: Volume IOR

Posted: Fri Dec 13, 2019 9:07 pm
by Dade
wasd wrote: Fri Dec 13, 2019 7:55 pm I see. Then, is it possible to make something like Cycles Refraction node?
https://docs.blender.org/manual/en/dev/ ... ction.html
It is a node working on surfaces (like LuxCore glass, roughglass, etc.), not volumes so it is not applicable to your problem.

Re: Volume IOR

Posted: Fri Dec 13, 2019 10:01 pm
by wasd
Dade wrote: Fri Dec 13, 2019 9:07 pm It is a node working on surfaces (like LuxCore glass, roughglass, etc.), not volumes so it is not applicable to your problem.
That's right. I just thought it might be good enough substitution for things like convections flows.