Search found 46 matches

by apaffy
Sat Jun 08, 2013 6:04 am
Forum: General Development
Topic: Questions about adjoint bsdf
Replies: 3
Views: 3506

Re: Questions about adjoint bsdf

So I need to compute the RR probability for the opposite direction too, and multiply it onto the opposite sampling pdf. My understanding is that even if I don't multiply that RR prob, the balance/power heuristic will at least gives me an unbiased result, but not optimal? Yep any set of weights that...
by apaffy
Mon Jan 07, 2013 11:22 am
Forum: ompf2
Topic: Latex formula support ?
Replies: 17
Views: 29324

Re: Latex formula support ?

Usually in mathjax this is using escaped ( instead of [. Seems to work: here is \(y\frac{\sin(x)}{2}\) in the middle of a sentence... :)
by apaffy
Tue Oct 02, 2012 6:55 pm
Forum: ompf2
Topic: Attachment file size
Replies: 2
Views: 5720

Re: Attachment file size

Is there a known issue with attachments at the moment? I'm trying to create a topic but the "upload attachment" button in the first post is reporting the following (hash varies):

Could not upload attachment to ./files/79_b1a54adefb9e2f677b2af2f3bf2a1068.
by apaffy
Thu Sep 06, 2012 12:05 pm
Forum: General Development
Topic: Source of non-symetric scattering : refraction ?
Replies: 7
Views: 4083

Re: Source of non-symetric scattering : refraction ?

Thanks ingenious, we agree then. :)

So has anyone implemented basic radiance in their approach (so also using basic solid angle measure everywhere) or is it normal to just handle the asymmetry manually?
by apaffy
Thu Sep 06, 2012 10:24 am
Forum: General Development
Topic: Source of non-symetric scattering : refraction ?
Replies: 7
Views: 4083

Re: Source of non-symetric scattering : refraction ?

How do they not cancel out? When there are no non-specular bounces within a medium, connections must use an eye subpath that enters and leaves the medium the same number of times, so has equal numbers of (e1/e2)^2 and (e2/e1)^2 in the adjustment for asymmetry along this eye subpath. These mathematic...
by apaffy
Thu Sep 06, 2012 9:28 am
Forum: General Development
Topic: Source of non-symetric scattering : refraction ?
Replies: 7
Views: 4083

Re: Source of non-symetric scattering : refraction ?

Well, my understanding is that unless you have non-specular bounces within some medium, the two boundaries (in and out of the medium) cancel out and it does not affect the image. I've always been interested in implementing the basic radiance approach described by Veach, but not yet attempted it. Wou...
by apaffy
Fri Aug 31, 2012 3:16 pm
Forum: General Development
Topic: BDPT & Lights hits
Replies: 5
Views: 3335

Re: BDPT & Lights hits

I'm saying that when the eye subpath hits anything , you can first check if that surface is emissive. If it is, handle it and only consider the emission function when deciding if this vertex is an angular delta function (just as you would if sampling this surface as a light source for the start of t...
by apaffy
Fri Aug 31, 2012 2:46 pm
Forum: General Development
Topic: BDPT & Lights hits
Replies: 5
Views: 3335

Re: BDPT & Lights hits

Yes you should handle light hits in BDPT. Using the usual convention of s light subpath vertices and t eye subpath vertices, this is the s=0 case. There's no need to stop the eye subpath (in PT or BDPT) unless there is no BSDF at this vertex. It's up to you whether you want the light sources in your...
by apaffy
Wed Aug 29, 2012 10:55 am
Forum: General Development
Topic: PDF of DoF
Replies: 8
Views: 5726

Re: PDF of DoF

I find it's easiest to consider a thin lens camera model as the dual of an area light with a spot-like emission model: * You sample the surface of the lens (i.e. the aperture in this model) for a position. So this has an area pdf of 1/area for the area of the lens. * For that position, you sample an...
by apaffy
Tue Aug 21, 2012 10:09 pm
Forum: General Development
Topic: MIS BPT with Russian Roulette
Replies: 16
Views: 11588

Re: MIS BPT with Russian Roulette

It would have been more helpful of me earlier to recommend you add some ability to save out images as follows: * A weighted image for each (s,t) combination * A weighted image for each path length (i.e. s+t) The first suggestion is so that you can ensure that combinations are zero/non-zero as expect...

Go to advanced search