Shadow rays transparency for path tracers (aka hybrid glass)

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happyboy
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Re: Shadow rays transparency for path tracers (aka hybrid glass)

Post by happyboy » Wed Oct 09, 2019 4:14 am

Dade wrote:
Tue Oct 08, 2019 5:51 pm
lacilaci wrote:
Tue Oct 08, 2019 4:28 pm
Just yesterday I had some werid crazy request on removing some shadows and reflections, it's a lot of work "photoshopping" it out but in cycles(also corona vray etc..) I just enable/disable some object flags or rayswitch to modify those features and I'm done...

I know the community around luxcore somehow seeks ultimate realism, but in reality clients want fancy looking shit, not simulation (my case).
The problem is not that I don't want to fake, it is that we trace light in both directions (i.e. backward and forward, from eye and lights) plus we have very often MIS (i.e. we trace the same path in different ways).
This mean that any asymmetrical light behavior (eye Vs light) can easily lead to some inconsistent/messed rendering. Cycles can do some stuff because it traces rays in a very specific way. Some aspect of the general "ray switch" concept can not be generalized. This "shadow rays transparency" it is however a step in that direction.
I'm on the same boat with lacilaci, plus I need to be able to trade realism for speed, not just fake things, so I need a lot of flexibility. But as the voting shows, very few people need these flexibility :(

Is it possible to only support these features in some very specific render engine, like PATHCPU and PATHGPU only, also some forbidden "feature combination"? When one of the faking features are enabled, you can do some very strict checking and refuse to render, instead of giving inconsistent/messed renderings.

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Re: Shadow rays transparency for path tracers (aka hybrid glass)

Post by marcatore » Wed Oct 09, 2019 6:58 am

Same boat of lacilaci and happyboy.

As much flexibility I have, better it is.
Let's see how development will go on.

This feature is more than welcome...so I hope that some useful but not iperrealistic tricks will always have room here. :)

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Dade
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Re: Shadow rays transparency for path tracers (aka hybrid glass)

Post by Dade » Wed Oct 09, 2019 7:50 am

happyboy wrote:
Wed Oct 09, 2019 4:14 am
Is it possible to only support these features in some very specific render engine, like PATHCPU and PATHGPU only, also some forbidden "feature combination"? When one of the faking features are enabled, you can do some very strict checking and refuse to render, instead of giving inconsistent/messed renderings.
It is already happening with this feature: it is limited to Path and ignored by BiDir.
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happyboy
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Re: Shadow rays transparency for path tracers (aka hybrid glass)

Post by happyboy » Wed Oct 09, 2019 10:33 am

Dade wrote:
Wed Oct 09, 2019 7:50 am
It is already happening with this feature: it is limited to Path and ignored by BiDir.
That's really nice. Thanks!

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Re: Shadow rays transparency for path tracers (aka hybrid glass)

Post by Sharlybg » Wed Oct 09, 2019 12:27 pm

With such kind of feature we are really becoming an ultimate render BOX well done :ugeek:
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B.Y.O.B.
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Re: Shadow rays transparency for path tracers (aka hybrid glass)

Post by B.Y.O.B. » Thu Oct 10, 2019 10:28 am

I have added support for this feature to BlendLuxCore, it's available as "Shadow Color" in the material output node.

However, I'm getting some serious fireflies when using it: https://youtu.be/kXUYarqcL-8?t=5
Scene attached.
Attachments
shadow_transparency_fireflies.zip
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Dade
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Re: Shadow rays transparency for path tracers (aka hybrid glass)

Post by Dade » Thu Oct 10, 2019 1:40 pm

B.Y.O.B. wrote:
Thu Oct 10, 2019 10:28 am
I have added support for this feature to BlendLuxCore, it's available as "Shadow Color" in the material output node.

However, I'm getting some serious fireflies when using it: https://youtu.be/kXUYarqcL-8?t=5
Scene attached.
I should have fixed the problem.
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