On Fri, Mar 6, 2015 at 5:03 PM, benson chepkwony <bchepk...@att.net> wrote:
> 3. Can we Modify/Edit these libraries such as: OpenCL, Opennurbs and
> Rhino3D folks or should we write a ray tracer from scratch, let say if we
> need to optimize it?
> 4. Is NURBS used to find ray intersection on objects? and what about
> OpenCL Code does it also do the same thing as NURBS? which one is better?
>
NURBS are just another primitive. The BRL-CAD rendering architecture uses
the ray tracing algorithm. So it has an implementation of a ray/NURB
intersection algorithm in order to render NURBS.
OpenCL is just a C like programming language with vector processing
extensions.
> I am interested in working on the "NURBS Optimization and Cleanup" and I
> would like to optimize its algorithm as this often plays a pivotal role in
> improving performance. This is just one classic place to optimize.
> To optimize ray tracer, I am planning on conducting a couple of these
> steps:
> 1. Implementing Kd-tree structure.
> 2. Implementing Bezier clipping method for NURBS Surface
> 3. Implementing BVH Ray traversal
> 4. Implementing Bounding Volume Hierarchy
> 5. Fine-tuning a NURBS-curve by specifying different weight
> with knot-vector
>
> Bounding Volume Hierarchy:
> In order to reduce intersection cost, a bounding volume should be drawn
> around each polygon.
>
You seem to be assuming BRL-CAD triangulates the NURBS surfaces before the
ray-tracing step but I am not sure that is what they are doing.
> You also mentioned that:
> "The way ray tracing currently occurs, there’s even room to speed up
> primitives on the host (CPU) by an order of magnitude or better ensuring
> better data coherency and eliminating branch logic."
> Because you mentioned it, I would like to look further in this area.
>
> If you want to work on that check out these papers:
"Design for Parallel Interactive Ray Tracing Systems"
"An Application of Scalable Massive Model Interaction using Shared-Memory
Systems"
which describe the implementation of the Manta ray-tracer. Manta is a an
open-source parallel ray tracer which has ray bundle optimizations.
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