Search found 9 matches

by dawelter
Thu Feb 22, 2018 8:44 am
Forum: Visuals
Topic: My little path tracer
Replies: 6
Views: 1056

Re: My little path tracer

Bidirectional path tracing! The first correct image! Well, as far as I can tell ;)
cornelbox5.jpg
cornelbox5.jpg (351.36 KiB) Viewed 127 times

High variance at 128 bidirectional random walks per pixel. Paths are weighted by one over the number of techniques that can generate the path. Implementation of MIS pending ...
by dawelter
Wed Feb 07, 2018 7:56 am
Forum: Visuals
Topic: My little path tracer
Replies: 6
Views: 1056

Re: My little path tracer

Thank you! Meanwhile I have a better pic. Something about the clouds strikes me as odd. Still a nice second try if you ask me. :-) atmosphere_cloudy.jpg To test my algorithms needed a material that has a "delta peak" plus a continuous density, so I implemented a dielectric material with a ...
by dawelter
Sat Jan 20, 2018 2:05 pm
Forum: Visuals
Topic: My little path tracer
Replies: 6
Views: 1056

Re: My little path tracer

Been working on my path tracer. Implemented table lookup for the height profile of collision coefficients. After some more work I could reproduce the blueness of the evening sky due to absorption by ozone. atmosphere_fisheye_ozone_compare.jpg Now there is support for area lights - in the form of tri...
by dawelter
Mon Dec 11, 2017 12:42 pm
Forum: Visuals
Topic: My little path tracer
Replies: 6
Views: 1056

Re: My little path tracer

Trying to reproduce results from Peter Kutz's Sky Render. Using 10 discrete wavelengths, no ozone, purely exponential density decrease. Something is wrong. Much too greenish for my taste. atmosphere_fisheye1.jpg atmosphere_fisheye2.jpg My approximation to the solar emission spectrum might be inadequ...
by dawelter
Sat Dec 09, 2017 9:30 am
Forum: General Development
Topic: Why is volumetric emission proportional to absorption coefficient?
Replies: 5
Views: 1358

Re: Why is volumetric emission proportional to absorption coefficient?

I found an interesting lecture script. http://www.ita.uni-heidelberg.de/~dullemond/lectures/radtrans_2012/Chapter_3.pdf Section 3.3 Eq 3.9. As I understand, ultimately it is a matter of definition motivated by thermodynamics of a special case. I imagine that the same particles that block light along...
by dawelter
Sat Dec 09, 2017 8:39 am
Forum: Visuals
Topic: My little path tracer
Replies: 6
Views: 1056

My little path tracer

This came out of my path tracer. cornelbox3.jpg Unfortunately convergence stagnated after some 10k samples per pixel. Not unexpected since it is a difficult scene. Lit by two point lights through the holes in the ceiling. I haven't implemented area lights. The medium has chromatic collision coeffici...
by dawelter
Sun Nov 26, 2017 10:44 am
Forum: General Development
Topic: Weighted delta tracking question
Replies: 4
Views: 1187

Re: Weighted delta tracking question

Ah all right. The sky is blue. It works! :lol: Single Lambda. atmosphere_single_lambda.jpg Spectral. Same number of samples per pixel. Higher render time but the result is worth it. atmosphere_spectral.jpg Edit. I managed to do a crude derivation of why this works. Basically taking the delta-source ...
by dawelter
Sat Nov 25, 2017 2:45 pm
Forum: General Development
Topic: Weighted delta tracking question
Replies: 4
Views: 1187

Re: Weighted delta tracking question

Thanks! It's true. I had the impression that there needs to be another factor 1/p_surf. But you are right. I made a quick implementation in python https://github.com/DaWelter/ToyTrace/blob/master/misc/deltatracking.py. It seems to work fine as you say, with the minor exception that I take 1/P_s inst...
by dawelter
Sat Nov 11, 2017 3:57 pm
Forum: General Development
Topic: Weighted delta tracking question
Replies: 4
Views: 1187

Weighted delta tracking question

Hello, I read the recent paper on Spectral and Decomposition Tracking by Kutz et al. http://drz.disneyresearch.com/~jnovak/publications/SDTracking/index.html I want to use weighted tracking methods in my own toy path tracer. Following the PBRT book pg 889, the incident radiance is composed of two te...

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