Search found 49 matches

by koiava
Thu Feb 04, 2016 9:08 am
Forum: General Development
Topic: A better way to sample a sphere (w.r.t. solid angle)
Replies: 16
Views: 22168

Re: A better way to sample a sphere (w.r.t. solid angle)

Useful conversion from Theta to Alpha. I also used this for cylindrical lights and good thing is that angle at light sample is Alpha+Theta and you can use it easily to calculate pdfs :)
by koiava
Fri Jan 15, 2016 9:38 am
Forum: General Development
Topic: super fast mbvh4 traversal and triangle intersection
Replies: 3
Views: 5069

Re: super fast mbvh4 traversal and triangle intersection

Well done! great improvements :) I tried once multifrusta packet tracing with 2 level BVH and remember that there was problems with packet transformations. If one ray in packet hits leaf of upper BVH you have to transform whole packet to leaf space to continue traversal in lower leaf BVH. As I guess...
by koiava
Thu Jul 02, 2015 12:24 pm
Forum: General Development
Topic: pbrt-v3 source code now available
Replies: 23
Views: 24797

Re: pbrt-v3 source code now available

We might have separate Pdf functions but returning sample and sampling Pdf from sampling function I think is more clear. Is there any case when you are sampling something and you doesn't need to know pdf?
by koiava
Thu Jul 02, 2015 8:56 am
Forum: General Development
Topic: pbrt-v3 source code now available
Replies: 23
Views: 24797

Re: pbrt-v3 source code now available

Hello Matt, Really good news! As I see, there is great major features and improvements, congrats! I'll definitely buy a new book! I have a question about code, there you have sampling function for shape(sphere), and in addition you have function for Pdf? What is the reason to separate those two. Pra...
by koiava
Thu Jul 02, 2015 8:28 am
Forum: General Development
Topic: Ideas request for a specific raytracing application
Replies: 28
Views: 20105

Re: Ideas request for a specific raytracing application

Environment Illumination is really great for such type of CAE applications. As the final shading result is dependent on 2 factors, brdf and light, variance coming from both parts will effect on final result. Brdf sampling is really easy, you generate some reflected directions proportional to your BR...
by koiava
Sun Jun 28, 2015 10:03 am
Forum: General Development
Topic: Ideas request for a specific raytracing application
Replies: 28
Views: 20105

Re: Ideas request for a specific raytracing application

As this is very specific case, when you have PCB board, you can increase efficiency of different parts of your renderer. Most of performance goes on determining Visibility, To increase performance of evaluating visibility you definitely need good acceleration structure. 1. Geometry will be static in...
by koiava
Tue Apr 07, 2015 11:42 am
Forum: General Development
Topic: Out-Scattering problem
Replies: 6
Views: 5851

Re: Out-Scattering problem

The paper for Residual Ratio Tracking will be a good reference for you. http://drz.disneyresearch.com/~jnovak/publications/RRTracking/index.html If you want to compute transmittance in in-homogeneous media in unbiased way, you can use Woodcock tracking. Furthermore, in the paper a better method RRT...
by koiava
Tue Apr 07, 2015 8:47 am
Forum: General Development
Topic: Out-Scattering problem
Replies: 6
Views: 5851

Re: Out-Scattering problem

Let's consider the eye point x0, the nearest surface point x1, the point sampled on a light source y0. You mean your renderer samples a few points(xp) along x0x1 and connects xp and y0, add a contribution attenuated by the factors T(y0, xp) and T(xp, x0), followed by adding contribution from the su...
by koiava
Mon Apr 06, 2015 7:27 am
Forum: General Development
Topic: Out-Scattering problem
Replies: 6
Views: 5851

Out-Scattering problem

Hello everyone, I'm really new in participating media rendering, experimenting around this last few weeks( here is my example of single scattering in homogeneous medium) and I'm encountered some problems. I'm using inverse square law for light attenuation from point light sample, but this law is cor...
by koiava
Thu Apr 02, 2015 8:55 am
Forum: General Development
Topic: cosine lobe sampling PDF
Replies: 11
Views: 15263

Re: cosine lobe sampling PDF

In Physically Based Rendering one of the most important factor is Energy Conservation. This means that in every scattering event reflected energy isn't greater than the energy what he received. So, in this case every BRDF must be normalized in such way that if you integrate over hemisphere using thi...