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Problem with bump map

Posted: Wed Oct 31, 2018 8:10 pm
by wasd
I can't get any bump from brick texure.

fBM diffuse color:
1.png
fBM bump:
2.png
Brick diffuse color:
3.png
Brick bump:
4.png

Re: Problem with bump map

Posted: Wed Oct 31, 2018 11:21 pm
by wasd
Bump texture is grey background with black and white lines and black square on it.
Cycles bump:
b1.png
Luxcore bump:
b2.png
Look at the shadows at square depression.

test scene:
bump_bug_b2.zip
(90.3 KiB) Downloaded 10 times
hdri: https://hdrihaven.com/hdri/?h=green_point_park

Re: Problem with bump map

Posted: Mon Nov 05, 2018 4:26 pm
by wasd
b1.png
b2.png
bump_lines_2.png
bump_lines_2.png (409 Bytes) Viewed 231 times
edit:
b4.png

Re: Problem with bump map

Posted: Thu Nov 08, 2018 9:25 am
by Mango3
I would better use a normal or displacement map for these types of larger raised or embossed structures. Especially if you want to animate the scene and change view direction.
Bump maps are good for small surface variations like pores or wrinkles on a skin. They don't change the actual surface geometry, just fake the illusion of depth (normal maps are the same in this regard).
Maybe also check your surface normals.

Re: Problem with bump map

Posted: Thu Nov 08, 2018 10:17 am
by lacilaci
Don't know much about this issue.
But overall I found it very hard to work with bump mapping. Sometimes higher values "break" the shader and sometimes they don't. Worse case was when in a scene where I was building asset everything looked ok, but then in main scene under different lighting it was wrong and I had to further tweak the shader... Not even mentioning how stronger bump exagerrates shadow terminator on round objects.
I hope that at some point this will get looked at cause it can be a big pain in the ass.

Re: Problem with bump map

Posted: Thu Nov 08, 2018 8:54 pm
by kintuX
wasd wrote:
Mon Nov 05, 2018 4:26 pm
The attachment b1.png is no longer available
The attachment b2.png is no longer available
The attachment bump_lines_2.png is no longer available
Works fine - you got your UV mapping rotated by 90°.

So, maybe it's this UV map orientation that's buggy?
I would imagine, no matter how the map is oriented, resulting effect should always depend on bump and lighting properties.
Bump_OK.jpg
Lighting: Sun&Sky, Tonemapper: Analog Film - Kodachrome 200CD

& Couple of tips:
For "Bump" (Normal, Displacement, Roughness...) textures set Gamma to 1 (Linear) as feature expects "Value", not "Color".
To help your self orientate better apply the use of compass, especially with generic textures (ie. as in cartography).

Re: Problem with bump map

Posted: Thu Nov 08, 2018 11:29 pm
by wasd
kintuX wrote:
Thu Nov 08, 2018 8:54 pm
So, maybe it's this UV map orientation that's buggy?
Nope. It's obvious that's it's bump that's bugged. I don't think that's intended behaviour.

Re: Problem with bump map

Posted: Mon Nov 12, 2018 8:43 am
by Dade
The result running inside Blender or with LuxCoreUI is different:
bump.jpg
This explain some of the my confusion, I wasn't seeing the problem. This is quite strange, it may be a bug in BlendLuxCore :?:

Re: Problem with bump map

Posted: Mon Nov 12, 2018 9:18 am
by Dade
Dade wrote:
Mon Nov 12, 2018 8:43 am
This is quite strange
It is caused by exporting:

Code: Select all

scene.textures.139662654818312.mapping.uvrotation = 90
scene.textures.139662654818312.mapping.uvscale = 8 -8
scene.textures.139662654818312.mapping.uvdelta = 0 2
Vs.

Code: Select all

scene.textures.139662654818312.mapping.rotation = 90.000002504478161
scene.textures.139662654818312.mapping.uvscale = 8 -8
scene.textures.139662654818312.mapping.uvdelta = 0 2
What ?!?!

Re: Problem with bump map

Posted: Mon Nov 12, 2018 9:21 am
by B.Y.O.B.
Bug in UV mapping in LuxCore?