Search found 52 matches

by dawelter
Fri Aug 07, 2020 12:56 pm
Forum: General Development
Topic: qestion regarding "A null-scattering path integral formulation of light transport"
Replies: 3
Views: 867

Re: qestion regarding "A null-scattering path integral formulation of light transport"

Ha! Thank you very much. The project report was very helpful. To write the estimator as 1 --------------------------- pr + pg + pb ---- ---- ---- fr fr fr like in Eq. 4. was the key to make the algorithm practical. I "only" had to carefully handle edge cases with arithmetic operations, 0/0 and 0 x i...
by dawelter
Wed Jul 29, 2020 8:40 am
Forum: Visuals, Tools, Demos & Sources
Topic: My little path tracer
Replies: 35
Views: 19391

Re: My little path tracer

As the path guiding does not do as well as I'd like, I decide to do something else. Built quasi monte-carlo sampling into the forward path tracer. I'm using a 21201-dimensional Sobol sequence from Joe & Kuo https://web.maths.unsw.edu.au/~fkuo/sobol/index.html. I tried a 2d base pattern with rotation...
by dawelter
Wed Jul 08, 2020 6:20 pm
Forum: Visuals, Tools, Demos & Sources
Topic: My little path tracer
Replies: 35
Views: 19391

Re: My little path tracer

P.s.: Improved visualization. Spheres show the incident radiance. You can see the peaks from the main light. Overall non-zero values from indirect illumination. The boxes show the principal axes of the covariance matrices of the sample positions within the cells of the SD-tree. guiding_distribution_...
by dawelter
Wed Jul 08, 2020 4:00 pm
Forum: Visuals, Tools, Demos & Sources
Topic: My little path tracer
Replies: 35
Views: 19391

Re: My little path tracer

Had some time to also implemented the directional quad-tree representation from Müller et al. (2017) "Practical Path Guiding for Efficient Light-Transport Simulation". Here are some observations: Mixtures of Von Mises-Fischer (MoVMF) Distributions don't seem to fit as well to incident radiance sampl...
by dawelter
Fri May 08, 2020 7:07 am
Forum: General Development
Topic: qestion regarding "A null-scattering path integral formulation of light transport"
Replies: 3
Views: 867

Re: qestion regarding "A null-scattering path integral formulation of light transport"

Hi! Nice paper you found there. I try to answer because I may attempt to implement this for my renderer, too. It's just a wild guess, but the authors omitted from algorithm 1 what happens when the particle hits a surface. In Eq (9) there is the last term T(x,z)L^s(z,w) which adds the light from the ...
by dawelter
Sat Mar 14, 2020 2:48 pm
Forum: Visuals, Tools, Demos & Sources
Topic: My little path tracer
Replies: 35
Views: 19391

Re: My little path tracer

Thanks :-) I wasn't very much concerned with memory so far. However, I can tell that this scene uses 2k cells or so. Each of which has to store the coefficients for two mixtures - plus some statistics for the EM algorithm. To be frank, I haven't tested the algorithm on much else than this one scene ...
by dawelter
Wed Mar 04, 2020 7:56 pm
Forum: Visuals, Tools, Demos & Sources
Topic: My little path tracer
Replies: 35
Views: 19391

Re: My little path tracer

Another over-night render. Much better this time. torus_in_cube.jpg I switched to mixtures of Von Mises Fisher distributions and implemented tricks from the "Path Guiding in Production" paper (stochastic filtering and troughput clamping). Together with some parameter tweaking, this helped. Now I can...
by dawelter
Wed Mar 04, 2020 7:40 pm
Forum: General Development
Topic: Path tracing in games
Replies: 26
Views: 23830

Re: Path tracing in games

Oh yes! With volume rendering! Looks very pretty overall. A great start for a game :-)
by dawelter
Sat Feb 08, 2020 9:23 am
Forum: Visuals, Tools, Demos & Sources
Topic: My little path tracer
Replies: 35
Views: 19391

Re: My little path tracer

Here is a first result from my attempt to implement path guiding following the "Path Guiding in Production" paper. So far I have surface guiding only. My ingredients are: * KD-tree inspired by "Practical Path Guiding for Efficient Light-Transport Simulation" by Müller et al.(2017) * Gaussian Mixture...
by dawelter
Sat Feb 08, 2020 9:02 am
Forum: Visuals, Tools, Demos & Sources
Topic: My first Supersize-Image
Replies: 22
Views: 9322

Re: My first Supersize-Image

Yes. You are right. Big scene plus directional light is a problem.

Would you spend more time on scenes in general? I believe you have many cool algorithms, but little material to exploit them ;-)