Information sought on rtrace_dc_2305 program


I am looking at, a fork of the RADIANCE mirror repository maintained by NREL ( which includes the source code for the DAYSIM suite.

The README says:

Programs maintained here that require manual intervention to compile (in src/rt):

  • rtrace_dc
  • rtrace_dc_2305

I am looking for information on rtrace_dc_2305. I will be asking them (the MIT Daysim project above) the following questions:

  • where is the source code for rtrace_dc_2305 (it doesn’t seem to exist in
  • how do I build rtrace_dc_2305?
  • what manual intervention is required to build it?
  • I need to build it for Linux - Is that possible? Your web page says ‘Programs in this repository compile on Windows (VS2013) and Mac (XCode)’ Does that imply that it not possible to compile them on Linux? - I ask because I have a slightly modified copy of Daysim 4.0 which allows building for Linux, and when I build it, it produces an executable for rtrace_dc, but not one for rtrace_dc_2305 (just like your version, it does not contain source code for rtrace_dc_2305).

But I thought I’d also ask here because rtrace_dc is a copy of rtrace, a Radiance program, and because you have helped me in the past to build Radiance for Linux.

I am running Daysim’s gen_dc program with the -dds option and it is falling over because it cannot find rtrace_dc_2305:

  • Do you know anything about rtrace_dc_2305?
  • How does it relate to rtrace_dc or rtrace?
  • Does source code for it exist?
  • If not, is the idea that rtrace_dc_2305 can be manually created by modifying rtrace_dc or rtrace?

Any information you may have that could help me figure out how to provide rtrace_dc_2305 to gen_dc (on Linux), will be greatly appreciated.

Thank you in advance for your help,

Philip Schwarz

I’ve already replied to this on GitHub, but here on the Radiance forum, my first question would be why you even want to use rtrace_dc_2305. Unless you have a specific requirement to use that software, you will have a much easier time using rcontrib instead.


Hello Nathaniel,

Thanks for getting back to me here and on Github.

my first question would be why you even want to use rtrace_dc_2305

I need to to call gen_dc with the -dds option. I have a colleague who installed Daysim on Windows and he can successfully do that. When I try to do that on Linux, I get the following

My colleague can see rtrace_dc_2305.exe as part of the installation on Windows. I cannot find the source code for rtrace_dc_2305, nor can I find any documentation saying that generation of a rtrace_dc_2305 binary on Linux is optional, or that explains how to generate the binary.

If I can’t resolve the problem then I can’t use the -dds option on Linux!

It looks like the way daysim depends on rtrace_dc_2305 is that it generates a file, called static_system.dir-dir.ab0.dc, which contains the following command invoking rtrace_dc_2305:

# RADIANCE 4.1a; with Photon Map Extension 4.3.1, Daysim Extension
# /usr/local/bin/daysim-radiance/rtrace_dc_2305  -h -I+ -oc -aa 0.150000 -ab 0 -ad 256 -ar 32 -as 20 -dj 0.700000 -dr 0 -ds 0.000000 

Do you have any further thoughts on how to get gen_dc -dds to work on Linux?

Thank you in advance for your help.


I’ve updated the CMake file and documentation on GitHub to explain how to compile rtrace_dc_2305 as well as I understand it. Use it at your own risk.