Shadow Terminator problem

Discussion related to the Engine functionality, implementations and API.
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lacilaci
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Re: Shadow Terminator problem

Post by lacilaci » Sun Aug 11, 2019 9:32 am

provisory wrote:
Sun Aug 11, 2019 9:27 am
After some comparisons I think again, that something is not perfect with LuxCore bump mapping.

Left side is highly subdivided and has displacement modifier with the bump texture.
Right side is low poly and has bump mapping with the same bump texture.

Cycles:
bump-test3-cycles.jpg


LuxCore after shadow terminator taming:
bump-test3-luxcore_new.jpg


LuxCore before it:
bump-test3-luxcore_old.jpg
Thanks, this is actually a better testscene than my own I think.
It is clear that luxcore was wrong even before, just in a different way. Now I say again, as Farbigewelt mentioned cycles might have issues of it's own... Some sort of magic is needed to have perfect bump mapping in luxcore

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Dade
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Re: Shadow Terminator problem

Post by Dade » Sun Aug 11, 2019 11:01 am

I will be out of the town for one week, I will look into this problem when I'm back.
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provisory
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Re: Shadow Terminator problem

Post by provisory » Sun Aug 11, 2019 11:47 am

Dade wrote:
Sun Aug 11, 2019 11:01 am
I will be out of the town for one week, I will look into this problem when I'm back.
Thank you, and have a nice rest!

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lacilaci
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Re: Shadow Terminator problem

Post by lacilaci » Sun Aug 11, 2019 11:55 am

Dade wrote:
Sun Aug 11, 2019 11:01 am
I will be out of the town for one week, I will look into this problem when I'm back.
Yes, I believe you find a way to make this work!
I'll try to prepare some nice sunny scene/project to put the terminator fix through some test.

kintuX
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Re: Shadow Terminator problem

Post by kintuX » Sun Aug 11, 2019 12:43 pm

lacilaci wrote:
Sun Aug 11, 2019 6:39 am
...
this problem is related to caustic cache I complained about it a week ago here: viewtopic.php?f=4&t=1271

if you disable the caustic cache everything works ok
A-OK. Narrowed it down to Periodic Update (OCL).
Thanks for the tip.

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lacilaci
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Re: Shadow Terminator problem

Post by lacilaci » Sun Aug 11, 2019 12:51 pm

kintuX wrote:
Sun Aug 11, 2019 12:43 pm
lacilaci wrote:
Sun Aug 11, 2019 6:39 am
...
this problem is related to caustic cache I complained about it a week ago here: viewtopic.php?f=4&t=1271

if you disable the caustic cache everything works ok
A-OK. Narrowed it down to Periodic Update (OCL).
Thanks for the tip.
Hm, interesting... Anyway, I hope that the cache will be deprecated and we'll have lighttracing+VM replacing everything caustic related.

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lacilaci
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Re: Shadow Terminator problem

Post by lacilaci » Mon Aug 12, 2019 3:08 pm

playing around some more with different textures and procedurals and it looks like it all works nicely unless there is a big contrast in the texture itself.
bumps.jpg
So something like leather pattern or textile pattern itself can work really nicely even with stronger bumps. Problem arises with textures that have bigger contrast. When textures or procedurals have big contrasty variations then stronger bump pushes some values too far and those black spots start to appear.

maybe some trick to prevent shading normal pointing away from camera at glancing angles could keep the bump quality but prevent those black spots?

Racleborg
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Re: Shadow Terminator problem

Post by Racleborg » Mon Aug 12, 2019 3:17 pm

@lacilaci

The materials on those headphones look awesome to me. Any advice on where I might be able to learn how to do that? Would it be ok to see the file or even just the node setup?

Thank you

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lacilaci
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Re: Shadow Terminator problem

Post by lacilaci » Mon Aug 12, 2019 3:25 pm

Racleborg wrote:
Mon Aug 12, 2019 3:17 pm
@lacilaci

The materials on those headphones look awesome to me. Any advice on where I might be able to learn how to do that? Would it be ok to see the file or even just the node setup?

Thank you
It's pretty basic, all of my materials usually are:
shader_nodes.jpg
Can't giveaway these textures, but probably any generic leather pattern can work (just make sure there is no big contrast in the texture or bump mapping breaks)

Racleborg
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Re: Shadow Terminator problem

Post by Racleborg » Mon Aug 12, 2019 3:26 pm

Thank you. I really appreciate the help. :)

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