Page 18 of 23
Re: Hybrid Back/Forward path tracing (aka BiDir without MIS)
Posted: Sun Jul 07, 2019 8:34 am
by lacilaci
epilectrolytics wrote: Sun Jul 07, 2019 8:09 am
I tested several engines with path depth = 8 and 100 samples:
EnginesTest.jpg
LightCPU performs far better in terms of noise and speed than all other engines, even BiDir, for caustics, direct and indirect light!
It only lacks display of specular bodies and lights which it cannot do by design.
I'd like to see an option for full light tracing in the new hybrid engine where the path tracer only provides those missing parts.
Like PGI light tracing seems to be a gold mine ready to improve all kinds of things with
Disturbing finds:
BiDir looks different (strange dark corners) than Hybrid, that should not be the case given both are unbiased.
PathMetro is not able to get reflective caustics which I think it should do.
interesting finds.
looks like something is wrong with pathocl direct light sampling
Re: Hybrid Back/Forward path tracing (aka BiDir without MIS)
Posted: Sun Jul 07, 2019 9:09 am
by epilectrolytics
B.Y.O.B. wrote: Sun Jul 07, 2019 8:27 am
But is LightCPU faster than PathOCL? I doubt it.
I can't believe it myself but apparently it is.
Screenshot after 60 seconds, LightCPU with 200 samples vs Hybrid PathOCL with 1800 samples on RTX 2070 + GTX 1060!
Only PGI would be faster but light tracing is unbiased (and easy to set up).
The problem is as Laci has mentioned elsewhere, PathOCL struggles with shadow converging.
LightCPU is the ultimate beast destroying them all
Re: Hybrid Back/Forward path tracing (aka BiDir without MIS)
Posted: Sun Jul 07, 2019 9:15 am
by B.Y.O.B.
I would be careful with conclusions after only testing one scene.
Try some more complex scenes from our example scene repository.
By the way, what's your CPU?
Re: Hybrid Back/Forward path tracing (aka BiDir without MIS)
Posted: Sun Jul 07, 2019 9:45 am
by epilectrolytics
See my signature, it's a Ryzen 2700X.
You are probably right that this advantage will not hold for complex scenes.
I just tested the Classroom and Benchmark scenes and they don't look well.
But because light tracing cannot connect to the camera from specular surfaces it does not work with glossy materials as well, so that would be one reason.
It needs to be combined with path tracing to account for that.
(Edit: Path tracing only for first hit = glossy or specular because light traces everything else till last hit = diffuse or scattering.)
Still I think it should be tested if full light tracing can make the Hybrid engine even better than it already is!
Re: Hybrid Back/Forward path tracing (aka BiDir without MIS)
Posted: Sun Jul 07, 2019 9:50 am
by bnzs1
is there are plans to expose setting of Hybrid Back/Forward path tracing in blender for 2.2 version ot it done for 2.3 version?
Re: Hybrid Back/Forward path tracing (aka BiDir without MIS)
Posted: Sun Jul 07, 2019 10:39 am
by B.Y.O.B.
bnzs1 wrote: Sun Jul 07, 2019 9:50 am
is there are plans to expose setting of
Hybrid Back/Forward path tracing in blender for 2.2 version ot it done for 2.3 version?
It is already exposed, but you need the 2_79_maintenance branch:
https://github.com/LuxCoreRender/BlendL ... aintenance
Re: Hybrid Back/Forward path tracing (aka BiDir without MIS)
Posted: Mon Jul 08, 2019 3:34 pm
by bnzs1
Dade wrote: Thu Jun 27, 2019 12:38 pm
I'm going to use this as manifesto:
(aka "if you use something else, you are out of your mind"
)
hi. can you share this scene with setting in blender for left part of screen? i can't understand how to use this Hybrid Back/Forward path tracing.....
Re: Hybrid Back/Forward path tracing (aka BiDir without MIS)
Posted: Mon Jul 08, 2019 4:05 pm
by epilectrolytics
bnzs1 wrote: Mon Jul 08, 2019 3:34 pm
hi. can you share this scene with setting in blender for left part of screen? i can't understand how to use this Hybrid Back/Forward path tracing.....
Hi,
here is the blend file:
Have you installed the recent blender add-on from the 2.79 maintenance branch on GitHub?
Then you can activate light tracing as indicated in this screenshot:
Re: Hybrid Back/Forward path tracing (aka BiDir without MIS)
Posted: Mon Jul 08, 2019 4:48 pm
by PetrT
have 2.79b and 2.2 beta 2
updates makes nothing
this option does not appear
Re: Hybrid Back/Forward path tracing (aka BiDir without MIS)
Posted: Mon Jul 08, 2019 5:06 pm
by B.Y.O.B.
You need this branch:
https://github.com/LuxCoreRender/BlendL ... aintenance
(Click the green "clone or download" button, download zip, then place LuxCore binaries in the "bin" folder like described
here).
If you don't get it to work you will have to wait for the next release.
