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1 vote
0 answers
94 views

Why my bsdf can not pass Chi2test?

I implemented a MicrofacetTransmission in nori. But it can not pass all Chi2test when alpha is large(>= 0.4 or ?),part of chi2test is passed.And I can not found the problem.Can someone help me? ...
bin guo's user avatar
  • 31
0 votes
1 answer
441 views

Path tracing: How to ensure we are sampling a direction vector within the visible hemisphere of a surface?

Given a surface Normal vector of an intersection point, how can one generate a random direction vector that is guaranteed to be in the visible hemisphere? The way I ...
Amir's user avatar
  • 241
0 votes
0 answers
86 views

Considering a path generated by bidirectional path tracing under a different strategy

Say I have constructed a path, using bidirectional path tracing (BDPT), consisting of a light subpath $y$ with $s=2$ vertices and a camera subpath $z$ with $t=3$ camera vertices. Now I want to ...
0xbadf00d's user avatar
  • 203
0 votes
0 answers
53 views

Distribution of the first vertex on a camera subpath in bidirectional path tracing

Suppose we are sampling camera rays of a perspective camera with a finite aperture. The PBRT implementation of the sampling scheme looks like this: ...
0xbadf00d's user avatar
  • 203
0 votes
0 answers
212 views

Multiple Importance Sampling in Bidirectional Path Tracing

I'm trying to understand the computation of the path density described in the book Physically Based Rendering. They assume that a path $$x=(x_0,\ldots,x_{n-1})=(q_0,\ldots,q_{s-1},p_{t-1},\ldots,p_0)$$...
0xbadf00d's user avatar
  • 203
3 votes
0 answers
81 views

Predicting reflectance functions from complex surfaces

There are three principal ways to obtain a BRDF. We can Derive an analytic formula using physical principles Use simulation given an assumed or measured model of the surface microgeometry Measure the ...
Arjan Singh's user avatar
  • 2,511
4 votes
1 answer
296 views

Tasks of a professional graphics programmer?

Currently I'm 16 and in high school and I love graphics programming and I'm seriously considering it as a career path. I was wondering what a day as a graphics programmer looks like for offline ...
Arjan Singh's user avatar
  • 2,511
3 votes
0 answers
521 views

Mathematics of Sub Surface Scattering

Can somebody help explain the mathematics of Sub Surface Scattering in a Path Tracer based on the Diffuse Approximation in A Practical Model for Subsurface Light Transport ? I would like someone to ...
Arjan Singh's user avatar
  • 2,511
4 votes
1 answer
105 views

How is measured BRDF data recorded?

How is measured BRDF data recorded? Like the MERL BRDF Database. What kind of equipment is used and what are the key values that need to be recorded? I know one place this data was used was in the ...
Arjan Singh's user avatar
  • 2,511