Where the bump gets strange

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mischterlampe
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Re: Where the bump gets strange

Post by mischterlampe » Thu Nov 19, 2020 3:49 pm

Dade wrote:
Thu Nov 19, 2020 9:57 am
Can you post a test scene with something like a cube or a sphere and the same material ?
Hi, here is the file.
https://drive.google.com/file/d/13TIrYy ... sp=sharing

Inside of it, there is the 16baked map and precedural noises.
You can use cycles and the procedural map for the best results, regardless of how close you are to the surface. That's what I expected.
There is also the 16k map in the cycles material tree to have a reference.
If you then swith to luxcore the 16k map is plug into the bump. The result is similar to the 16k cycles viewport rendering, which is good, but I want to get away from maps with such a resolution.
Then I tried to pipe this 16k map trough a triplanar bump, resulting in flat looking reflections.
Next is the Blender Stucci procedural map, remapped to fit the greyscale of the 16kmap, resulting in flat looking reflections. Then my though was: "Maybe these blender procedural maps aren't integrated well in luxcore". This is why I tried the fBM with clamped values from 0-1. But the result is also flat.

Keep an eye on the edge of the red material in the bottom left, where the light fades out. This is a good place to spot the bump.
Thanks for helping
Last edited by mischterlampe on Fri Nov 20, 2020 5:51 am, edited 1 time in total.

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B.Y.O.B.
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Re: Where the bump gets strange

Post by B.Y.O.B. » Thu Nov 19, 2020 5:52 pm

mischterlampe wrote:
Wed Nov 18, 2020 11:12 pm
How is process of using a procedural map when rendering? Is it baked to an image?
No, procedural textures are not baked to images. They don't have a resolution.

mischterlampe
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Re: Where the bump gets strange

Post by mischterlampe » Thu Nov 19, 2020 7:28 pm

Thank you for the clarification.

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Dade
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Re: Where the bump gets strange

Post by Dade » Fri Nov 20, 2020 10:28 am

mischterlampe wrote:
Thu Nov 19, 2020 3:49 pm
Hi, here is the file.
https://drive.google.com/file/d/13TIrYy ... sp=sharing
Your test scene is using vertex geometry displacement (so it is obviously discrete), not bump mapping :!: :?: :!:

Have you posted the wrong one or misunderstood how BlendLuxCore works ?
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mischterlampe
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Re: Where the bump gets strange

Post by mischterlampe » Fri Nov 20, 2020 11:03 am

Oooookkay, now I'm really confused.

I thought this is the bump workflow:
why_not_a_bump.PNG

And I thought this is vertex displacement which is not in the sample scene:
is_this_vertex_displacement.PNG

Where did I set vertex displacement in the sample scene and what is the correct way to do a bump?
Thanks, I appreciate your help.

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Dade
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Re: Where the bump gets strange

Post by Dade » Fri Nov 20, 2020 11:21 am

mischterlampe wrote:
Fri Nov 20, 2020 11:03 am
And I thought this is vertex displacement which is not in the sample scene:
It is:

disp.jpg
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mischterlampe
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Re: Where the bump gets strange

Post by mischterlampe » Fri Nov 20, 2020 11:33 am

I see what you mean, but this is the cycles shader, there is a luxcore material, too.
This cycles shader is for reference.

Sorry, I should have saved it with the luxcore material shader selected.
Attachments
cycles shader tree.PNG

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Dade
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Re: Where the bump gets strange

Post by Dade » Fri Nov 20, 2020 12:22 pm

You need to adjust your the material bump sampling distance. This is a render with the default value of 0.001:

i1.jpg

And this is the same exact scene with a value of 0.00001:

i2.jpg

"A picture is worth a thousand words"

@B.Y.O.B, is the the material ".bumpsamplingdistance" parameter exposed in BlendLuxCore ?

P.S. changing this parameter is not required for image based bump mapping because the sampling distance is always 1 pixel in this case.
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Re: Where the bump gets strange

Post by B.Y.O.B. » Fri Nov 20, 2020 12:55 pm

This parameter is not yet exposed in the addon.
What would be good min/max limits for it, and what could be a good descriptive tooltip text?

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Dade
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Re: Where the bump gets strange

Post by Dade » Fri Nov 20, 2020 1:06 pm

B.Y.O.B. wrote:
Fri Nov 20, 2020 12:55 pm
This parameter is not yet exposed in the addon.
What would be good min/max limits for it, and what could be a good descriptive tooltip text?
The default sampling distance is 0.001 (1 mm), smaller value should be used if the bump (procedural) texture has smaller details (like in the case above).
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