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glass (newbie question)
Posted: Tue Aug 25, 2020 8:35 pm
by jon
Hi All,
Just started playing with LuxCore ... it's amazing
. Thanks to the development team for all the hard work!
Quick question about glass. I tried creating a simple glass material and applying it to a sphere (foreground) and, well, I failed.
Material is defined as:
Code: Select all
scene.materials.glass_test.type = glass
scene.materials.glass_test.kr = 0.2 0.2 0.2
scene.materials.glass_test.kt = 0.5 0.5 0.5
Should there not be specular reflections? Clearly I've missed something obvious. Can someone steer me in the right direction?
Cheers,
Jon
PS. Not trying to do volume rendering here -- just a thin glass surface.
Re: glass (newbie question)
Posted: Tue Aug 25, 2020 10:44 pm
by Dade
You need to define the glass index of refraction (aka IOR) with the property ".inetriorior":
https://github.com/LuxCoreRender/LuxCor ... ll.scn#L23
Re: glass (newbie question)
Posted: Wed Aug 26, 2020 12:20 am
by jon
Ah, got it, thanks. I'd assumed the default value (1.5) would take effect.
Follow up question: What's the physical meaning of kr and kt? I assume kr is a multiplier that acts on the specular-reflection component (which is determined by IORs)? And kt acts on the non-reflected remainder? Just want to make sure I understand the physical basis. (I can also check the source code if this isn't documented elsewhere
.)
Re: glass (newbie question)
Posted: Wed Aug 26, 2020 10:38 am
by Dade
jon wrote: Wed Aug 26, 2020 12:20 am
Follow up question: What's the physical meaning of kr and kt? I assume kr is a multiplier that acts on the specular-reflection component (which is determined by IORs)? And kt acts on the non-reflected remainder? Just want to make sure I understand the physical basis. (I can also check the source code if this isn't documented elsewhere
.)
They are the specular reflection and transmission scale factors. You can set both to (1.0, 1.0, 1.0) for a perfect specular transmission/reflection without any kind of attenuation.
Re: glass (newbie question)
Posted: Wed Aug 26, 2020 2:27 pm
by jon
Perfect. Thanks, Dade.