Shadow Terminator problem

[Dade]

I am not sure if this is relevant to the currently discussed Bump issue, but I don't appear to be getting any Bump effect be with the Checkerboard Texture like it does with other textures such as Distorted Noise?

This should be normal: the bump is proportional to the difference of 2 adjacent pixels, if the pixels have the same color (like inside a check), there is no difference and the normal is unmodified. So it is modified only on the sharp edge between 2 checks.

[Dade]

I think it is related, that strong bump mapping flips normals:

Normals aren't really flipped, I checked the values, they just become tangent to the plane so the point emits light 90 degree over and 90 degree under the plane. Stronger is the bump map and more points will have tangent normals and more light will be emitted under the plane.

I would consider this expected (or just a different type of problem).

[Dade]

I decoupled the UV scale and strength, so changing the UV scale doesn't affect bump mapping strength anymore.

[FarbigeWelt]

I decoupled the UV scale and strength, so changing the UV scale doesn't affect bump mapping strength anymore.

Thank you this is much more intuitive because uv map is 2D and its scaling is not expected to change z even if uv map is used as bump map (with influence on z looking).

[lacilaci]

I decoupled the UV scale and strength, so changing the UV scale doesn't affect bump mapping strength anymore.

good news

I tried to lookup if other renderers didn't have to deal with this type of issue...

And for most it's related to glossy reflection under extreme circumstances, diffuse component never turns black in any other renderer.

Anyways, here's best I found, but I'm not sure if it's of any use for luxcore:
https://blogs.unity3d.com/2017/10/02/mi ... h-tracing/

[kintuX]

I decoupled the UV scale and strength, so changing the UV scale doesn't affect bump mapping strength anymore.

Terminator tamed Looks nice.

But is it known that Caustics & Bump don't work well together?

Also, something with OCL is causing Lux to freeze when stopping the render. Within Blender or UI only. And I don't get any error.
IIRC, similar bug appeared before.
Here (scene for LuxcoreUI) it happens when after I Pause it, change the Halt time and press Apply. Freeze! To kill.

The attachment FreezingScene.7z is no longer available

[Dade]

Anyways, here's best I found, but I'm not sure if it's of any use for luxcore:
https://blogs.unity3d.com/2017/10/02/mi ... h-tracing/

I have the code for this is: https://github.com/LuxCoreRender/LuxCor ... f.cpp#L149 (http://www.aconty.com/pdf/bump-terminat ... ia2019.pdf)

This year new SIGGRAPH paper is supposed to be an improvement over that one.

[Dade]

I decoupled the UV scale and strength, so changing the UV scale doesn't affect bump mapping strength anymore.

Terminator tamed Looks nice.

But is it known that Caustics & Bump don't work well together?

The "taming" is currently limited to DIFFUSE and GLOSSY materials: https://github.com/LuxCoreRender/LuxCor ... f.cpp#L243

I haven't yet tried how it works with SPECULAR materials.

[Dade]

Here (scene for LuxcoreUI) it happens when after I Pause it, change the Halt time and press Apply. Freeze! To kill.

I will try to reproduce the problem.

[lacilaci]

So do we know why are these dark patches and how to fix that?

I wonder how is it that other renderers don't suffer from this. Maybe some dirty tricks to limit normals or bump strenght?