Converting models from AutoCAD to Radiance
Method 1
If you’re committed to using AutoCAD as your modeling program, there are Georg Mischler’s AutoCAD export utilities. They only work on older versions of AutoCAD, though:
Method 2
Another option for the AutoCAD user is the dxf2rad utility.
If you use ACIS solids, you can use 3DSOUT (in AutoCAD) to export a polygonal model, then bring it back in with 3DSIN, then back out with DXFOUT, then use dxf2rad to convert the geometry to a Radiance scene description. A bit circuitous, but it would work.
(originally posted by Rob Guglielmetti on the Radiance Online mailing list: http://www.radiance-online.org/pipermail/radiance-general/2007-August/004412.html)
Method 3
Another possibility is to export the model using the 3DS format (File→Export menu, or 3DSOUT command) and then use the 3ds2mgf and mgf2rad commands.
3ds2mgf is distributed with Radiance, but not built by default. To build it, go to the ray/src/cv/mgflib directory and type the command:
make 3ds2mgf
This works under a UNIX-like system, or a Windows environment with the MinGW or Cygwin environments installed.
Then, copy the resulting executable to the appropriate directory (e.g., /usr/local/bin).
John Mardaljevic has provided a script to automate the 2 pass conversion:
#!/bin/csh -f set tds = $1 set nam = $tds:r 3ds2mgf $tds mgfilt '#,c,cct,cmix,cspec,cxy,cyl,ed,f,ies,ir,m,o,p,prism,rd,rs,sides,sph,td,ts,v,xf,fh' $nam.mgf | mgf2rad -m mat$nam.rad >! $nam.rad rm $nam.mgf $nam.inc
The Radiance binaries downloadable from this page should include 3ds2mgf by default.