Free raytracer for optical engineering.

January 23, 2012 11:40 AM

Do any open source raytracers support an output of luminance incident on a surface? I want to determine the distribution of light on a surface in a scene based on the sun position. There are commercial packages that support this, but with the popularity of open source raytracing packages, is there one that can do what I need?

If there aren't any, I'll have to program it. Any recommendations as which would be the easiest to modify to produce the output I want would be appreciated as well.

posted by demiurge to Computers & Internet (4 answers total)

POVRay ? It's FOSS and does almost everything.
posted by k5.user at 11:53 AM on January 23, 2012

I'd look into PBRT and/or its descendant, LuxRender. They're "physically based" renderers, which more or less means they actually simulate the way light works rather than using algorithms that happen to look good.
posted by rivenwanderer at 1:53 PM on January 23, 2012

Response by poster: LuxRender is the way I would want to go, but according to this there's no way currently to get the output I want. I was wondering if anyone has done something similar, in terms of direct luminance output from a surface, before I go digging into the LuxRender code.
posted by demiurge at 1:57 PM on January 23, 2012

As I understand it, you'd have an easier time getting the numbers you want from a radiosity approach rather than a raytracer. (OTOH, as I understand it, most renderers use some radiosity techniques now.) Radiance is a rather old hybrid raytracer-radiosity program which might be well suited to what you're doing. Back when I knew more about these things, hybrid approaches had problems producing physically-correct output, but it sounds like Radiance attempts to produce physical results.

(While searching for that dimly-remembered program I also ran across DIALux.)
posted by hattifattener at 8:25 PM on January 23, 2012