This doesn't look right… is something wrong with my glass refraction?

[happysmash27]

I noticed that glass looks weird inside of this modification of a downloaded vehicle. Even after I removed the accidental duplicate plane I made and connected the two planes of glass, it still looked weird:



I made an additional plane to check, just in case some weird modelling escaped me, but it looks weird as well:



Does anyone know what might have gone wrong? I am using Blender 2.79b LuxCore 2.0 rc1 on Gentoo Linux. Even if everything is behaving correctly, I know something must be off, because I'm pretty sure that vehicle glass does not refract in a way that only shows the sky normally…

[B.Y.O.B.]

Have you made sure that the windows have thickness and that the normals are pointing in the right directions?
The easiest way to add thickness to a plane is to add a solidify modifier.

[happysmash27]

Yes; the car window had two planes which I connected to make a solid, and the experimental one is just a cube which has been thinned along one axis.

[happysmash27]

Anyone?

[happysmash27]

Ooh, this is interesting... It appears that if I get a cube, scale it, then add material, it works fine, but if I add material then manually modify it, it has the bug...

[happysmash27]

I made the glass slightly thicker and now it doesn't happen anymore on the manually modelled one. What is going on here?

[happysmash27]

Specifically, I changed the distance from the centre from 5mm to 1cm...

[B.Y.O.B.]

The glass sheet is probably so thin that it causes numerical precision issues.
If you use the latest alpha version, there is an "Advanced LuxCore Settings" button in the scene properties, unit panel.
You can try to lower or raise the "min. epsilon" value and see if that helps. (E.g. try to lower it to 0.000001 first).

Another option is to make the glass sheet thicker.