(Open)Subdiv and Displacement shapes

Discussion related to the LuxCore functionality, implementations and API.
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Dade
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Re: (Open)Subdiv and Displacement shapes

Post by Dade » Thu Oct 24, 2019 3:17 pm

I haven't finished...
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marcatore
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Re: (Open)Subdiv and Displacement shapes

Post by marcatore » Thu Oct 24, 2019 3:38 pm

I hope that your last words give us room for something that reduce subdivision using camera distance (as you've already done) but along the same mesh...so at face level and not mesh level.
I'm quite sure that it will be really appreciated.

Racleborg
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Re: (Open)Subdiv and Displacement shapes

Post by Racleborg » Thu Oct 24, 2019 4:30 pm

it was so slow to make people cry
:lol: :lol:

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Dade
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Re: (Open)Subdiv and Displacement shapes

Post by Dade » Fri Oct 25, 2019 8:58 am

Added an Harlequin shape (mostly to debug meshes):

harlq.jpg

It set the mesh vertex colors to an Harlequin pattern.
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Egert_Kanep
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Re: (Open)Subdiv and Displacement shapes

Post by Egert_Kanep » Sun Nov 03, 2019 3:20 pm

Cool idea for mesh displacement, to even out normals. Could LuxCore's displacment benefitfrom this technique?
https://youtu.be/Vx_kYEUvYCA?t=575

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Dade
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Re: (Open)Subdiv and Displacement shapes

Post by Dade » Sun Nov 03, 2019 4:02 pm

Egert_Kanep wrote:
Sun Nov 03, 2019 3:20 pm
Cool idea for mesh displacement, to even out normals. Could LuxCore's displacment benefitfrom this technique?
https://youtu.be/Vx_kYEUvYCA?t=575
He is using the trick to export to OpenVDB and than back to smooth the normals, this pretty much equivalent to some kind of normal filtering to reduce the amount of displacement where the normals change very fast. It could be done even better by using some kind of Ambient Occlusion value (i.e. check how near are other surfaces and scale the displacement to avoid self-intersections).

It is something I can do, not sure how to prioritize it (i.e. I'm not sure how important it is) because it should be useful only with some quite extreme displacement.
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Egert_Kanep
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Re: (Open)Subdiv and Displacement shapes

Post by Egert_Kanep » Sun Nov 03, 2019 11:15 pm

I guess if topology is evenly spread it doesn't matter. But for things like bricks and sharp hardsurface things it might be useful. I think we can replicate this with blender modifiers to check if it's really useful or not

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lacilaci
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Re: (Open)Subdiv and Displacement shapes

Post by lacilaci » Wed Jan 01, 2020 9:07 am

subdivision shape does this weird thing where some vertices remain sharp.. Some parts of the monkey are nicely subdivided and smoothed while some remain sharp, why is that?
Annotation 2020-01-01 100504.jpg
hmm, it seems it depends on camera angle, so this is the keep sharp borders option I assume...

I'd like to know if it's faster to use blender's subdivision surfaces or use the shape node, also which would use less memory. Or maybe there isn't any difference?

Maybe it would be nice to have the subdivision shape being used together with simplify shape and have it as a rendertime adaptive subdivision surface instead of blender's uniform subdivisions? Is the simplify shape taking into account distance from camera?

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Dade
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Re: (Open)Subdiv and Displacement shapes

Post by Dade » Wed Jan 01, 2020 10:38 am

lacilaci wrote:
Wed Jan 01, 2020 9:07 am
I'd like to know if it's faster to use blender's subdivision surfaces or use the shape node, also which would use less memory.
I would say, use LuxCore subdivision if you are going to use displacement (and may be simplify) otherwise use Blender. There isn't really a reason to leave subdivision to LuxCore if you aren't going to use some other feature.
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Sharlybg
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Re: (Open)Subdiv and Displacement shapes

Post by Sharlybg » Tue Jan 21, 2020 1:34 pm

Please guys what is the correct node tree and file format for Vector displacement ?
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