Search found 20 matches

by sriravic
Fri Aug 22, 2014 12:10 pm
Forum: General Development
Topic: questions about hair rendering
Replies: 5
Views: 4730

Re: questions about hair rendering

Hi With regards to hair rendering, using curves directly over tessellation has its own advantages and disadvantages. 1. Reduced memory consumption. Typically curves are modelled as splines or bezier curves which are just a bunch of control vertices. Hence we use very less memory compared to tessella...
by sriravic
Wed Jul 02, 2014 7:28 pm
Forum: General Development
Topic: avoid rejection sampling
Replies: 6
Views: 5727

Re: avoid rejection sampling

You can use cosine weighted sampling (pdf proportional to the cos(theta) term) which is where I feel its more important to sample since you're using a normal map to perturb the normals.
by sriravic
Mon Jun 30, 2014 12:08 pm
Forum: General Development
Topic: understanding sampling, filters, motion blur, DoF,...
Replies: 14
Views: 9563

Re: understanding sampling, filters, motion blur, DoF,...

You never store objects with time. You store animated transforms (transforms that have a time value associated with them. PBRT to the rescue again.). With this animated transform, you can find the position of the object at any time and use that for intersecting. Note that animated transform blur (or...
by sriravic
Mon Jun 30, 2014 5:41 am
Forum: General Development
Topic: understanding sampling, filters, motion blur, DoF,...
Replies: 14
Views: 9563

Re: understanding sampling, filters, motion blur, DoF,...

Okay. So I'll try to answer your questions one by one in the order you've listed. 1. The primary objective of a sampler is to provide samples in a generic domain. They are not related to pixels per se but are used to get good sampling locations within a pixel [domain]. Think of the area of the pixel...
by sriravic
Wed May 14, 2014 5:47 am
Forum: General Development
Topic: MIS - BSDF evaluation
Replies: 0
Views: 3046

MIS - BSDF evaluation

Hi I would like to ask a few questions about the way the layered material system is handled in pbrt (atleast with respect to the path tracing integrator). 1. A material contains a BSDF which is nothing but a stack of bxdfs. During monte-carlo path tracing, at the intersection point, we can choose an...
by sriravic
Fri Jul 12, 2013 6:30 am
Forum: Visuals, Tools, Demos & Sources
Topic: Glitch Pictures anyone?
Replies: 81
Views: 125077

Re: Glitch Pictures anyone?

I guess I was trying to do conic rays.!!! Figured out finally the issue was caused by not doing a normalization of direction..!!
by sriravic
Thu Jan 17, 2013 5:14 am
Forum: General Development
Topic: transform sample ray to world coordinate
Replies: 1
Views: 2214

Re: transform sample ray to world coordinate

Does the ray use its own local coordinate system i.e the light's coordinate system? If so, you'll have to create a transformation matrix that changes the rays [origin,direction] to world transform. You can create a transformation matrix that is similar to the camera transformation creation.
by sriravic
Fri Nov 09, 2012 7:42 pm
Forum: General Development
Topic: Ray tracing performance
Replies: 2
Views: 3010

Ray tracing performance

Hello All,

I have a question regarding measuring of ray tracing performance. Various papers present the results as 'Million Rays Per second'. How is this value actually calculated?? Is it equal to (width * height * numSamplesPerPixel)/totalRenderTimeInSeconds?
by sriravic
Sat Jul 14, 2012 4:11 am
Forum: Links & Papers
Topic: Surface area of polytopes
Replies: 5
Views: 5412

Re: Surface area of polytopes

Actually I have been looking at your paper in the first place. Can you help me getting the source code for the actual project on which your paper 'Accelerated Building and Ray Tracing of Restricted BSP Trees' was based. I have a tough time in understanding the node structure used..
by sriravic
Wed Jul 11, 2012 6:52 pm
Forum: Links & Papers
Topic: Surface area of polytopes
Replies: 5
Views: 5412

Surface area of polytopes

Is there any efficient way of computing the surface area of k dimensional polytopes (k-dops)? I am looking at constructing RBSP trees on the gpu and was wondering if there was any efficient way of doing this.