Search found 75 matches

Mon Dec 04, 2017 2:31 pm
Forum: General Development
Topic: Why is volumetric emission proportional to absorption coefficient?
Replies: 7
Views: 15732

Re: Why is volumetric emission proportional to absorption coefficient?

Thanks for reply. I can find the volumetric emission term which proportional to absorption coefficient for example in, Jensen's Photon Mapping book, Spectral and Decomposition Tracking paper or Wojciech Jarosz's thesis. In the Jarosz's thesis reference, there is the following sentence by the equatio...
Tue Nov 28, 2017 6:19 pm
Forum: General Development
Topic: Why is volumetric emission proportional to absorption coefficient?
Replies: 7
Views: 15732

Why is volumetric emission proportional to absorption coefficient?

Hi, I have a simple question as in the title. Why is volumetric emission proportional to absorption coefficient? I often see the volumetric emission term is written as volumetric_emission_term_1.png I can also see another representation, volumetric emittance function (e.g. in Mark Pauly's thesis: Ro...
Sat Nov 25, 2017 4:02 pm
Forum: General Development
Topic: Weighted delta tracking question
Replies: 4
Views: 7762

Re: Weighted delta tracking question

The reason why I wrote 1 / (1 - P_n(x)) is that PBRT-v3's delta tracking implementation only cares about the interaction is null-collision or not, while the integral formulation in the paper simultaneously cares about three types of interaction (scattering, absorption(emission), null-collision). The...
Sun Nov 19, 2017 11:49 am
Forum: General Development
Topic: Weighted delta tracking question
Replies: 4
Views: 7762

Re: Weighted delta tracking question

Hi, In my understanding, T_r / p_surf becomes the weight computed by cumulatively multiplying the following single step weight: single_step_weight.png as in the SD tracking paper. If this is implemented by following PBRT's interface for example for GridDensityMedium::Sample(), it returns the above w...
Thu Jun 15, 2017 5:46 am
Forum: Visuals, Tools, Demos & Sources
Topic: My First Spectral rendering
Replies: 5
Views: 10823

Re: My First Spectral rendering

Cool

What is the material?
Do you implement Hero wavelength spectral sampling?
Mon May 22, 2017 11:08 am
Forum: General Development
Topic: Multi-wavelength free path sampling using ratio tracking
Replies: 7
Views: 9438

Re: Multi-wavelength free path sampling using ratio tracking

Nice work! :D Maybe it's also necessary to also consider the compensation for passtrough rays that leave the volume. Right, of course it needs consideration for such rays as you say. It corresponds to my code at l.80 in the current implementation: https://github.com/shocker-0x15/SLR/blob/master/libS...
Fri May 05, 2017 2:07 pm
Forum: General Development
Topic: Multi-wavelength free path sampling using ratio tracking
Replies: 7
Views: 9438

Re: Multi-wavelength free path sampling using ratio tracking

great!!!

Thanks!
Wed Feb 22, 2017 5:15 am
Forum: General Development
Topic: Multi-wavelength free path sampling using ratio tracking
Replies: 7
Views: 9438

Multi-wavelength free path sampling using ratio tracking

Hi, I'm curious about whether using ratio tracking for estimating Monte Carlo constribution (f(x) / p(x), not transmittance) with delta tracking for heterogeneous media is unbiased. We can get a MC contribution of free path sampling by delta tracking for a wavelength used for the procedure. There is...
Mon Jan 09, 2017 5:15 pm
Forum: General Development
Topic: Volumetric Pathtracing / Small UPBP
Replies: 4
Views: 13470

Re: Volumetric Pathtracing / Small UPBP

Sorry to be late. This procedure implicitly includes selection between the two terms with probability. select the case 1 with probability P_s select the case 2 with probability 1 - P_s P_s is a probability to perform evaluation on surface. case 1: immediately evaluate the attenuated radiance leaving...
Thu Dec 15, 2016 1:55 am
Forum: General Development
Topic: Volumetric Pathtracing / Small UPBP
Replies: 4
Views: 13470

Re: Volumetric Pathtracing / Small UPBP

Hi, As you know, volume light transport equation consists of two terms where the one is attenuated light L_s leaving a surface and the other is "the integral of" light gain L_a due to in-scattering and emission. L_i = T * L_s + int T * L_a ds * L_a is volumetric emission and in-scattering * The unit...