Search found 279 matches

by ingenious
Thu Jul 26, 2018 11:12 am
Forum: General Development
Topic: Emissive surfaces and visibility term
Replies: 6
Views: 1083

Re: Emissive surfaces and visibility term

In Veach's framework the measurement contribution of a path is always the same and it includes all cosines and inverse squared distances along the entire path. But a given path can be sampled in many different ways, i.e. via different techniques. The pdfs of some techniques will include some cosines...
by ingenious
Thu Jul 26, 2018 11:01 am
Forum: ompf2
Topic: Something's wrong with the RSS and forum posting
Replies: 3
Views: 644

Re: Something's wrong with the RSS and forum posting

Everything seems to be back to normal, thanks a lot Jacco!
by ingenious
Tue Jul 24, 2018 4:43 pm
Forum: ompf2
Topic: Something's wrong with the RSS and forum posting
Replies: 3
Views: 644

Something's wrong with the RSS and forum posting

I now always get a message "No route found for "GET /ompf2/viewtopic.php" when posting in the forum or when opening a topic from the RSS feed. Any ideas?
by ingenious
Tue Jul 24, 2018 4:41 pm
Forum: Links & Papers
Topic: Primary Sample Space Path Guiding
Replies: 3
Views: 602

Re: Primary Sample Space Path Guiding

I was initially excited by the title of the paper but I soon found a deal-breaker. With primary-/path-space path guiding, the dimensionality of the ideal cache is infinite. But the radiance field in the scene in world space is only a 4D or max 5D function (surface/volume + direction). Prior path gui...
by ingenious
Tue Jul 24, 2018 4:36 pm
Forum: General Development
Topic: Emissive surfaces and visibility term
Replies: 6
Views: 1083

Re: Emissive surfaces and visibility term

TL;DR: If a ray randomly hits a light source, you should not be multiplying by the cosine as it's importance sampled and cancels out. In Veach's integral formulation of light transport it's all crystal clear. The radiance emission at every point on a diffuse light source is uniform (i.e. the same in...
by ingenious
Thu Mar 01, 2018 1:48 am
Forum: Visuals
Topic: My little path tracer
Replies: 16
Views: 7160

Re: My little path tracer

Will investigate. Hints appreciated ;-) Yeah, doesn't look correct. The most likely reason is that the MIS weights corresponding to the different techniques for constructing a path don't sum up to one. This in turn is probably due to incorrect/inconsistent path pdf computation. What has helped me g...
by ingenious
Tue Jul 11, 2017 4:30 pm
Forum: General Development
Topic: MIS with IBL
Replies: 14
Views: 8612

Re: MIS with IBL

The problem is that the probability you use for choosing a light source is itself a random variable. If you write out the estimator you're building with your sampling techniques, its expected value won't be what you want. To get an unbiased estimator, you'll need to divide not by that random probabi...
by ingenious
Mon Apr 17, 2017 4:58 pm
Forum: Tools, Demos & Sources
Topic: Implementation for Blue-noise Dithered Sampling
Replies: 26
Views: 15214

Re: Implementation for Blue-noise Dithered Sampling

The idea ideas not adding a deterministic (blue-noise) number to a random number. In fact, the idea is to get rid of the randomness altogether - you use the deterministic number to post your pattern, instead of using a random number. Regarding the (0, 0.99) vs (0, 0.01) issue, the answer is that it ...
by ingenious
Thu Feb 02, 2017 3:59 pm
Forum: Tools, Demos & Sources
Topic: Implementation for Blue-noise Dithered Sampling
Replies: 26
Views: 15214

Re: Implementation for Blue-noise Dithered Sampling

To be honest, i don't even know if it can bring any real benefit for anything that is not directly visible from the camera. After all one exploits the human visual system here, so the higher dimensions/bounces should be better tackled via a properly distributed sample set (e.g. most likely some mod...
by ingenious
Tue Jan 31, 2017 6:33 pm
Forum: Tools, Demos & Sources
Topic: Implementation for Blue-noise Dithered Sampling
Replies: 26
Views: 15214

Re: Implementation for Blue-noise Dithered Sampling

toxie wrote:Would be interesting to hear your experiences when rendering with it, when optimizing for this 10D case. Cause IMHO the scheme should fall apart when using a large number of dimensions.


Indeed, in my experience it's hard (impossible?) to achieve high-quality blue noise in high dimensions :(

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