Search found 22 matches

by tomasdavid
Sun Aug 17, 2014 11:39 am
Forum: General Development
Topic: Comparison of spectral vs rgb rendering?
Replies: 9
Views: 7077

Re: Comparison of spectral vs rgb rendering?

For the extra spectral noise you definitely want to check out Alex Wilkie's EGSR 2014 paper on Hero Wavelength...
by tomasdavid
Sat Aug 16, 2014 2:51 am
Forum: General Development
Topic: Comparison of spectral vs rgb rendering?
Replies: 9
Views: 7077

Re: Comparison of spectral vs rgb rendering?

It really depends on your materials. For anything refractive, the slight dispersion effect in the refractions obviously reads more natural. For other stuff.. skin can be more realistic, you can probably do better hair (both have spectral models more or less readily available), but I don't think ther...
by tomasdavid
Mon Jun 02, 2014 6:59 pm
Forum: General Development
Topic: VCM GPU implementation (+ some extras)
Replies: 8
Views: 6724

Re: VCM GPU implementation (+ some extras)

Ah, for compaction purposes, got it. I have only fairly simple BRDFs (the most complicated is Ashikhmin-Shirley), so compacting for BRDFs didn't pay of for me. Also, as stated in the paper, on the newer generation (6xx, and it goes for 7xx as well) the compaction doesn't buy you as much as it did on...
by tomasdavid
Mon Jun 02, 2014 10:09 am
Forum: General Development
Topic: VCM GPU implementation (+ some extras)
Replies: 8
Views: 6724

Re: VCM GPU implementation (+ some extras)

Yo. ad 1/2) I am not entirely sure what do you intend to sort here. I don't think I sort anything in either of the two, but it's been a bit since I touched the implementation. ad 3) The MIS used is derived for connecting to all vertices of a single "companion" path. When you connect to a s...
by tomasdavid
Sun May 18, 2014 8:24 pm
Forum: General Development
Topic: UPS vs VCM?
Replies: 9
Views: 5325

Re: UPS vs VCM?

in smallVCM, I'm trying to "catch" only caustics, but couldn't find out how, I tried to output ConnectToCamera() only, but the result is all photons "not only caustics", what am I missing there to classify photons? You need ConnectToCamera for paths that have a flag that the pre...
by tomasdavid
Mon May 12, 2014 9:47 am
Forum: General Development
Topic: My Optix porting of SmallVCM (only PathTracer & BDPT)
Replies: 24
Views: 17399

Re: My Optix porting of SmallVCM (only PathTracer & BDPT)

I am not sure how it can be done, either :? I don't claim that such a thing is possible with stochastic hashing, though I admit that it might be misleading in the sketch. My dissertation contains a bit more details than the sketch on stochastic hashing, if someone else also wonders. Thank you very ...
by tomasdavid
Sat May 10, 2014 7:18 am
Forum: General Development
Topic: My Optix porting of SmallVCM (only PathTracer & BDPT)
Replies: 24
Views: 17399

Re: My Optix porting of SmallVCM (only PathTracer & BDPT)

#EDIT: Actually, the better answer is that I don't write into the hashed grid as soon as photons are generated. I trace all the rays, generate all the photons, and then write them into hashed grid at once. Unfortunately, the original approach to stochastic hash grid, as it is implemented, loses the...
by tomasdavid
Sun Feb 02, 2014 2:50 am
Forum: General Development
Topic: Choosing clamping limit in VPL rendering
Replies: 13
Views: 7687

Re: Choosing clamping limit in VPL rendering

My question is, wouldn't it be kind of "suboptimal" in the sense that we ignore the fact that the more VPLs you have in total, the lower each contribution becomes? For example, let's say we trace 100 light subpaths for each iteration and do 1000 iterations (i.e., we get O(100K) VPLs). If ...
by tomasdavid
Mon Jan 27, 2014 7:09 pm
Forum: General Development
Topic: Choosing clamping limit in VPL rendering
Replies: 13
Views: 7687

Re: Choosing clamping limit in VPL rendering

Glossy is one thing and should be treated with care but I'm not sure bidirectional is more efficient otherwise. Would be interesting to see some statistics. One of the main advantages of the paper, the limit on max path length of the compensating rays, works only when you know you have purely diffu...
by tomasdavid
Mon Jul 29, 2013 8:49 am
Forum: General Development
Topic: Computing Explicit Light Sampling Weights
Replies: 3
Views: 3656

Re: Computing Explicit Light Sampling Weights

I will suggest reading up on the MIS chapter of Veach thesis. You want the weight here, but also want weight near the "what if I hit a light by accident" point in the code. The code usually actually folds together the BRDF*both cosines / distance^2 and the PDF weight used for MIS and yes, ...

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