Replacing rtrace with accelerad_rtrace command

accelerad
1

Hello Radiance Community,

I am trying to use accelerad to speed up my scene generation. I am trying to implement an arbitrary clipping surface. A simple example I have used is two boxes (box and smallbox) and a clipping plane between them. I need one box to be clipped off (by using the plane as the clipping surface).

The command I am using is

vwrays -fd -vf outside.vf -x 400 -y 400 \
| rtrace -w -h -fd -opd 1st.oct | rtrace -w -ab 2 \
-fdc `vwrays -d -vf outside.vf -x 400 -y 400` 2nd.oct \
clipped.hdr; ximage clipped.hdr

where I would like to replace the rtrace command with the accelerad_rtrace one. There seems to be a problem with this because of the -opd parameter from what I could debug (the p parameter specifically).

Any guidance in this problem would be much appreciated.

Thank you in advance

2

Hi @Daniel,

The -o options allow rtrace to return an arbitrarily-sized collection of data, which isn’t practical on the GPU and probably scales poorly. However, your first rtrace call could probably be accomplished with no reflections (-lr 1), so I don’t see how you gain anything from GPU acceleration. I would suggest that you use accelerad_rtrace only for your second rtrace call to optimize performance.

3

Hello @Nathaniel_Jones ,

Thank you for your quick response, your solution worked but now I am faced with another problem, I have been playing around with the -lr and -lw parameters.

There seems to be some noise in the object and its shadow. Do you have any idea why is this happening?

Thank you in advance

4

Hi @Daniel,

The description of the problem you provided isn’t very clear, but my first suggestion is to adjust the ambient cache size.