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abahena
04-22-2012, 03:18 AM
Hi,
I want to build a raytracer for renderman any idea where to start, I mean using DSOs I already know the basics of a raytracer. I notice that GI in renderman its slow compared to other renders. I'm wondering if I cant implement a gpu raytracer perhaps using openCL or cuda via optix. Any dso examples will help.
Thanks,
Alexis

noizFACTORY
04-22-2012, 02:41 PM
Sorry, this doesn't answer your question but have you tried any of prman 16+ versions? Raytracing speed/quality is significantly faster in the latest releases.

abahena
04-22-2012, 05:35 PM
I only have access to 3Delight and Mantra

noizFACTORY
04-22-2012, 05:51 PM
3delight is a pretty decent raytracer as well. Have you tried using the "raytrace" hider? Also, you can post in the forums @ www.3delight.com (http://www.3delight.com) for direct answers from the devs.

Also, last I spoke to one of the devs, they did have a plan for gpu based stuff but since then I haven't heard or seen any public release from them on this. So you could probably ask them about it on their forums as well.

earlyworm
04-23-2012, 03:06 PM
Advanced RenderMan (http://www.amazon.com/Advanced-RenderMan-Creating-Pictures-Kaufmann/dp/1558606181) has info on how they implemented a rayserver to work with BMRT. The Siggraph course notes also has an abstract of the chapter... http://www.renderman.org/RMR/Publications/sig98.course11.pdf

rendermaniac
04-29-2012, 12:27 PM
I don't think it's a good idea writing a raytracer as a DSO. You will need to build your own acceleration structure and load all your objects into it etc, so you'd be making a complete renderer inside another renderer which really limits your options.

In my opiniion the best place to start is having a look at Physically Based Rendering by Matt Pharr and Greg Greg Humphreys and literally is all about their open source renderer PBRT (the book is the source code!) http://pbrt.org/

You may also want to look at Production Rendering: Design and Implementation http://www.amazon.com/Production-Rendering-Ian-Stephenson/dp/1852338210 . It is written by several high profile renderer authors.

As people have said prman and 3delight both have very good raytracing engines already. The big limits of these renderers are the initial REYES hiding (the minimum you can render is every vertex) and shading at ray hits (RSL gets its speed from batching points - which is difficult to do when raytracing).

Simon

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