LuxCoreRender Forums

Finger prints on glass, using roughness:

From my testing as you can see at the beginning of this post, using rough option makes the glass quite darker.

Taka wrote: ↑Fri Apr 05, 2019 6:28 pm From my testing as you can see at the beginning of this post, using rough option makes the glass quite darker.

Yes, i too found it too strong at first. But that's why "Math Divide" node is there, to lessen the effect.

PS
Here I divided by 25 & set Glass Color to pure White: & Divided by 50:

Thanks kintuX,
Here is another test using rough option.
First image regular glass
Second image rough option enabled, roughness set to 0.001(lowest I can set)
As you can see, something is not right.

Why not mix glass with matte?
Also instead of a texture driving roughness directly the texture could mix clear glass with rough glass (instead of matte), minimising the darkening effect.

epilectrolytics wrote: ↑Fri Apr 05, 2019 9:06 pm Why not mix glass with matte?
Also instead of a texture driving roughness directly the texture could mix clear glass with rough glass (instead of matte), minimising the darkening effect.

That works well! Thanks

B.Y.O.B. wrote: ↑Fri Apr 05, 2019 5:15 pm On Nvidia GPU, it looks exactly like on your end (green with PathOCL, blue with RTPathOCL).
On Intel OpenCL CPU device, it's also wrong, see attached image.
Maybe a bug in LuxCore after all?

I should have fixed this problem: it was a bug when using glossy coating with pure specular materials (i.e. glass, mirror).

Dade wrote: ↑Wed Apr 10, 2019 10:07 am

B.Y.O.B. wrote: ↑Fri Apr 05, 2019 5:15 pm On Nvidia GPU, it looks exactly like on your end (green with PathOCL, blue with RTPathOCL).
On Intel OpenCL CPU device, it's also wrong, see attached image.
Maybe a bug in LuxCore after all?

I should have fixed this problem: it was a bug when using glossy coating with pure specular materials (i.e. glass, mirror).

Maybe this fix is not yet in BlendLuxCore, or it's another bug, or not bug at all.
The rough glass with roughness of 0.001 has very strong transmissino color. Set the reflection color to pure red, and roughness of 0.001.
Mixed with clear glass, you need mix factor of 0.000001 in favor of clear glass, to make the rough glass red transmissino color fade out.

There are no changes required in the Blender addon to use this fix.
However, the latest daily build does not yet contain the fix: https://github.com/LuxCoreRender/LuxCore/commits/master

B.Y.O.B. wrote: ↑Wed Apr 10, 2019 3:04 pm There are no changes required in the Blender addon to use this fix.
However, the latest daily build does not yet contain the fix: https://github.com/LuxCoreRender/LuxCore/commits/master

I did build with last commit 6e4635d,