Rcontrib extract ray intersections and directions


I’m using rcontrib and dctimestep to evaluate radiation that is being reflected from the glazing of a building onto a test point. This is working well, however…

Now I would also like to save the world intersections (Px,Py,Pz) and directions (Dx,Dy,Dz) of the contributing rays. In the rcontrib manual, under the explanation of the -b option it mentions a way. Presumably should be straightforward but am struggling to replicate -.- .Would anyone be kindly able to offer a solution?

I’m quite new to Radiance, fresh out of school

Many thanks,

my code:
rcontrib -e MF:4 -f reinhart.cal -b rbin -bn Nrbin -m glazing -I+ -V- -ab 8 -ad 50000 -lw .00002 -lr 10 -faa scene.oct < testpoint.vf > viewmatrix.mtx

Hi Paul,

I’m not exactly sure what you are after, but it is possible to bin ray intersection points as well as directions, which is all you are binning with reinhart.cal. You would need to create a 2-dimensional binning function and combine it with the rbin output of reinhart.cal with a spatial binning operator. You would still not get individual ray intersections, since that’s not the way rcontrib works, but you would be able to get counts of when you were in a particular rectangular area.

Would this suffice?

Thanks very much for your reply Greg, with it I was able to get what I needed. And sorry for not being able to back earlier, seasonal activities in full swing.

I’d like to ask another rcontrib question that someone might be able to advise on:

Would anyone be able to suggest changes in my rcontrib input parameters to improve consistency/precision in the daylight coefficient calculation? Attached is a plot of 5 simulations I did at 1-minute timestep with an identical set of skymatrices but new rcontrib calculation for each. The test point is unobstructed, facing up. Which parameters would be best to reduce noise? Is it possible? I have tried a few changes with no luck so far.

Current parameters:
rcontrib -e MF:4 -f reinhart.cal -b rbin -bn Nrbin -m sky_mat -I+ -ab 8 -ad 50000 -lw .00002 -lr 10 -faa scene.oct < testpoint.vf > viewmatrix.mtx

Thank you!

Is the test point inside a building, or just naked outdoors (you said “unobstructed”)? If it’s outdoors, I don’t know what to suggest other than increasing -ad and decreasing -lw. For indoors, I would suggest just decreasing -lw (by a factor of 10 or more) and seeing if that makes a difference. MC noise is difficult to eliminate entirely…

Thanks very much for the suggestions. The point is naked outdoors

Good improvements with -ad 5000000 and -lw 0.000002. This is five different rcontrib runs like above.