Search found 7 matches

by dawelter
Sat Jan 20, 2018 2:05 pm
Forum: Visuals
Topic: My little path tracer
Replies: 2
Views: 354

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: 2
Views: 354

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: 760

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: 2
Views: 354

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: 790

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: 790

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: 790

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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