Search found 12 matches

by guo
Tue Aug 12, 2014 9:26 am
Forum: Links & Papers
Topic: Implementing Vertex Connection and Merging (tech report)
Replies: 12
Views: 13103

Re: Implementing Vertex Connection and Merging (tech report)

Hi, Can you elaborate more on the derivation of $d^{\text{VCM}}_1$ for $\mathbf{z}_1$ in equation (31)? And I found the intuitive definition of "vertex merging" in section 2.1 to be a bit confused. The original paper says that the PDFs of the same-length paths sampled by BDPT and PM should...
by guo
Sun Apr 27, 2014 1:02 am
Forum: Links & Papers
Topic: Joint Importance Sampling of Low-order Volumetric Scattering
Replies: 8
Views: 10144

Re: Joint Importance Sampling of Low-order Volumetric Scatte

Assuming I've understood your question the direction transformation correctly, my answer it that yes, this transformation is in fact needed. The standard (\theta, \phi) transformation you mention yields a uniform direction distribution over the sphere. You need to more aggressively warp the \theta ...
by guo
Sat Apr 26, 2014 2:13 am
Forum: ompf2
Topic: Latex formula support ?
Replies: 17
Views: 28539

Re: Latex formula support ?

Can you bring our beloved mathjax back?
Maybe I can help on that as I once experienced in PHP development.
by guo
Sat Apr 26, 2014 2:05 am
Forum: Links & Papers
Topic: Joint Importance Sampling of Low-order Volumetric Scattering
Replies: 8
Views: 10144

Re: Joint Importance Sampling of Low-order Volumetric Scatte

Hi, I love this paper and I have several small questions. The equation (42) is $$p(w_{u,v})=p(w)\left|\frac{dw}{dw_{u,v}}\right|\sin\theta_{dc}$$ Here why $\theta_{dc}$ is used instead of $\theta_{cb}$? And from equation (27) we know the singularity originates from $\frac{1}{\sin \theta_{cb}}$, whic...
by guo
Wed May 01, 2013 3:49 pm
Forum: ompf2
Topic: NEW SERVER
Replies: 23
Views: 19013

Re: NEW SERVER

well done. :D
by guo
Thu Dec 20, 2012 6:40 am
Forum: My First...
Topic: reason of shooting photon flux in photon mapping
Replies: 0
Views: 2898

reason of shooting photon flux in photon mapping

Hi all, In photon mapping, the total flux of an emitter is split into many small flux packets and then these packets are traced. And while packets are gathered for density estimation, total flux of gathered packets are divided by projected area of searching sphere to approximate irradiance assuming ...
by guo
Sun Nov 04, 2012 3:44 pm
Forum: My First...
Topic: rays get stuck due to total internal reflection
Replies: 0
Views: 2840

rays get stuck due to total internal reflection

Hi there, I implemented the ideal dielectric reflection and refraction BSDF, then rendered this glass of water with maximum ray bounces being limited to 16: http://i1339.photobucket.com/albums/o713/guozhou/glass.png As we can see, those dark edges correspond to rays which suffer from many many specu...
by guo
Wed Oct 24, 2012 11:00 am
Forum: My First...
Topic: mix BRDFs correctly
Replies: 3
Views: 4483

Re: mix BRDFs correctly

I can't be 100% sure, but by visual inspection, your MIS is not being done correctly. You're simply calling pdf(bRec), but you also need to factor in the probability of the two choices. In other words, you need the two separate pdfs(bRec), and you need to combine them into a mixed pdf to normalize....
by guo
Wed Oct 17, 2012 8:10 am
Forum: My First...
Topic: mix BRDFs correctly
Replies: 3
Views: 4483

Re: mix BRDFs correctly

OK, let me show off a result by path racing with next event estimate: http://i1339.photobucket.com/albums/o713/guozhou/1_zps196335a1.png 256 samples are generated for each pixel. The above eval() and pdf() are used in luminaire sampling, while sample() is used in BRDF sampling. However, since they a...
by guo
Fri Oct 05, 2012 5:09 am
Forum: ompf2
Topic: Spam
Replies: 33
Views: 31432

Re: Spam

Maintenance is not done yet. :) I need to upgrade to the latest version to get rid of all the spammers, but a previous attempt failed horribly making the admin panel inaccessible. I need to do a manual backup of the database (without using the build-in backup function), then reinstall, then restore...

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