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Re: Cold Fusion

Posted: Mon Jun 10, 2019 9:00 pm
by epilectrolytics
It should be possible with hitpoint normal to add a little opacity only to the top face of the prism.

Re: Cold Fusion

Posted: Mon Jun 10, 2019 9:17 pm
by B.Y.O.B.
Or just assign a null material to the top face, with same interior volume as the glass on the sides.

Re: Cold Fusion

Posted: Tue Jun 11, 2019 8:37 pm
by Fox
B.Y.O.B. wrote:
Mon Jun 10, 2019 4:53 pm
In theory, the beams would become visible if you use a homogeneous volume for the interior of the prism.
However, I could not get them to show even with that - I suspect that these are SDS paths (specular-diffuse-specular) which Bidir is unable to render.
I got them visible, but it's gonna take day or so to render, perhaps it can be speed up.

I made prism smaller ~ 6 cm. The world cube is ~ 81 cm.
Prism is a mix material of mat1 dispersion glass and mat2 rough glass of 0.3, mix factor 0.01

Prism volume is hetero, multi, step 2 mm, steps 128, absorption 0.7 at 1 m, scattering scale 10, asymmetry 0.9

World camera volume is hetero, multi, step 1 cm, steps 1024, scattering scale 0.3, asymmetry 0.5

Lasers are 1mm

Re: Cold Fusion

Posted: Thu Jun 13, 2019 1:35 pm
by Fox
:D BiDirVM and random, it's too noisy for 6 hour render. Multi scattering is off. BCD denoiser fell appart after denoising 1,4 hours, so it's the raw render.
Prism 6h BiDIrVM.jpg

Re: Cold Fusion

Posted: Thu Jun 13, 2019 2:22 pm
by FarbigeWelt
Fox wrote:
Thu Jun 13, 2019 1:35 pm
:D BiDirVM and random, it's too noisy for 6 hour render. Multi scattering is off. BCD denoiser fell appart after denoising 1,4 hours, so it's the raw render.

Prism 6h BiDIrVM.jpg
Hi Fox
I very like this render as noisy as is. Amazing what BirDirVM is capable of. Dispersion, reflections, scattering to call a few. The image looks rather like a painting than a computer rendered image. A little post process tweaking could do wonders. Maybe soft Gaussian smoothing and increasing saturation softly and the image is a real burner.

Re: Cold Fusion

Posted: Thu Jun 13, 2019 3:03 pm
by Fox
Thx FarbigeWelt
I tweak the materials to get some light behind mirrors, room walls were 0 0 0 black, perhaps not so good. And mirror reflection was 1 1 1, this i take down. Not sure what is good value for bidirvm.lightpath.count, i test with 1024, the first render had 131072.

Re: Cold Fusion

Posted: Thu Jun 13, 2019 4:59 pm
by epilectrolytics
Fox wrote:
Thu Jun 13, 2019 1:35 pm
Prism 6h BiDIrVM.jpg
Great lighting.
BiDirVM would really be the best unbiased engine if only it was usable...

Re: Cold Fusion

Posted: Sun Jun 16, 2019 6:43 pm
by epilectrolytics
Border render with 130 000 samples - BiDir SDS-paths done by camera rays finding the area lights without light rays.
I wonder if Corona-style guided path tracing could improve this?
border.jpg
border.jpg (21.07 KiB) Viewed 61 times

Re: Cold Fusion

Posted: Sun Jun 16, 2019 8:33 pm
by Fox
epilectrolytics wrote:
Sun Jun 16, 2019 6:43 pm
Border render with 130 000 samples - BiDir SDS-paths done by camera rays finding the area lights without light rays.
I wonder if Corona-style guided path tracing could improve this?
border.jpg
I think the prism is colliding little with bottom floor :roll:
I got this scene to render pretty clean with OIDN under 12 hours, seems to even work with classic BiDir.

With multi scattering enabled and russian roulette disabled, i was enable to make 1 pass to take 2500 seconds (bidir 64/64 x BiDirVM 256) :shock:
Multi off and russian roulette on, i got nice clean render.

On that render the multi is on and the russian roulette value is set from default 3 to 6. I should go back to multi off and RR at 3. Even OIDN has problem giving good denoising.
Here with scattering asymmetry down from 0.9 to 0.5 the light beam is stronger, but with classic engine the beam is blown out inside prism, don't know if the spectral rainbow will come out, perhaps it will.
55 passes.
55 Passes, multi scattering on.jpg
Prism BiDirVM.7z
(86.91 KiB) Downloaded 4 times

Re: Cold Fusion

Posted: Sun Jun 16, 2019 9:06 pm
by kintuX
@Fox
Noice 8-)

What's your CPU?