Search found 20 matches

by andersll
Sun Jul 09, 2017 8:48 pm
Forum: General Development
Topic: MIS with IBL
Replies: 14
Views: 5532

Re: MIS with IBL

One thing that I realized is that when the random selected light happens to be behind the point that is being evaluated the potential contribution is 0, and therefore the sky will be selected with a probability of 1. However, another light may in fact be visible, so when I stumble upon it the MIS p...
by andersll
Mon Sep 28, 2015 11:13 pm
Forum: General Development
Topic: Sobol' sequences
Replies: 11
Views: 9544

Re: Sobol' sequences

Yeah I think CMJ performs pretty well from what I've seen, but still suffers from the limitation that you've got to know your sample count up front.
by andersll
Mon Sep 28, 2015 11:08 pm
Forum: General Development
Topic: Sobol' sequences
Replies: 11
Views: 9544

Re: Sobol' sequences

I just tried halton this afternoon and found it to be slightly worse than sobol in a naive implementation. I also looked at your code and tried reordering the low dimensions as you do but found that gave me more noise than the default ordering. I think I need to spend some more time tweaking the imp...
by andersll
Mon Sep 28, 2015 3:19 pm
Forum: General Development
Topic: Sobol' sequences
Replies: 11
Views: 9544

Re: Sobol' sequences

Actually looking back at my code, both examples were with 1024 samples. At 4096 samples the 14,15 space is completely covered, although I think the 24,25 space needs 8192 samples to be covered. How does the Faure-permuted Halton perform at lower sample counts?
by andersll
Mon Sep 28, 2015 1:30 pm
Forum: General Development
Topic: Sobol' sequences
Replies: 11
Views: 9544

Re: Sobol' sequences

That does look a lot better, I'll give it a go, thanks! Does it have any bad 2d projections in other dimensions?
by andersll
Wed Sep 23, 2015 3:43 pm
Forum: General Development
Topic: Sobol' sequences
Replies: 11
Views: 9544

Re: Sobol' sequences

Thanks toxie. After thinking about it some more I'd sort of realised that was the case. I guess in the limit then the sequence explores the whole sample space in a nicely-distributed fashion, which isn't necessarily what I'm after.

What's considered "state of the art" these days?
by andersll
Mon Jul 27, 2015 5:56 pm
Forum: General Development
Topic: pbrt-v3 source code now available
Replies: 23
Views: 18144

Re: pbrt-v3 source code now available

In the BeckmannSample11 function in microfacet.cpp you have special logic to check for whether we're at normal incidence and sample the slope directly, but then the rest of the function continues as normal and *slope_x and *slope_y will be overwritten. Shouldn't the function return after line 48? ht...
by andersll
Sun Jul 05, 2015 3:15 am
Forum: General Development
Topic: Looking for textures for material preview scene
Replies: 2
Views: 3909

Re: Looking for textures for material preview scene

I have a Maya shaderball scene you can use as a starting point here (scroll down to the bottom of the page):
http://anderslanglands.com/alshaders/

It's set up for Arnold but should be easy to adapt for your purposes
by andersll
Wed Jun 10, 2015 2:18 am
Forum: General Development
Topic: Sobol' sequences
Replies: 11
Views: 9544

Sobol' sequences

I'm trying out Leonhard Gruenschloss's Sobol'-seqeunce generator from here: http://gruenschloss.org/ The first two dimensions look as expected (0,1): http://i.imgur.com/4iDfBKG.jpg but higher dimensions show the poor projections that I thought the "better 2d projections" paper was supposed...
by andersll
Tue Sep 02, 2014 3:38 pm
Forum: Links & Papers
Topic: GACV : robust numerical integration method
Replies: 2
Views: 5054

Re: GACV : robust numerical integration method

This sounds interesting! Can you share the preprint any other way? I can't create an account on that site to be able to view it.

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