BMRT

The Blue Moon Rendering Tools

BMRT is a Renderman-compliant renderer and is available for free from Exluna. It is made by Larry Gritz and supports ray-tracing and radiosity.

The best known Renderman-renderer is PRMan from Pixar. This is a scanline-renderer, no ray-tracing, no radiosity, but fast and expensive.

The rendering was made with the free BMRT. You could use PRMAN, if you had the money :)

ArchiCAD 6.0 *.rib-export

The first model was exported from ArchiCAD 6.0 (not supported in 6.5 anymore!) to the Renderman *.RIB format (using the ArchiCAD shaders).

	That version of ArchiCAD was shipped with a few shaders, but I had to edit them and recompile them to get something rendered at all. You can download them, but they probably need some more tweaking. Anyone who can make them work, can mail them to me and I'll put them on this site.
	Next I had to add a few "declare" statements in the RIB-file (they're included in the download) to get rid of most warnings and errors.
	Then you should surround all calls to using textures (for spotlights where they calculate a shadow map and for the background) with brackets "[" and "]".

The result is a flat shading, without shadows... The missing geometry is because I used the ArchiCAD-version at work, which doesn't allow using some of the library-elements I bought from SIMATEK.

Archi(CAD)2rad by Paul Bourke

Because I still had problems, I tried the program Archi2rad (download the Visual C++6 project, including compiled executable or look at the original from Paul Bourke) to convert the RIB-exported file to Radiance.

With the conversion (using "archi2rad -l -m -g name.rib > name.rad") and renaming the file "archicad" to "name.rib" it was possible to render the file, although the shadow map wasn't calculated correctly and no lighting is seen on the model.

3D Win Conversion

3DWin is a file-format conversion utility, in the shareware-market. It reads and writes a lot of different formats (and does it pretty well).

The next example was converted from the 3DS-file with the demo of 3DWin4, that didn't save the material settings, although the shadows turned up this time.

This was the default rendering.

This example is a tweaked version of the previous.

	The material settings were put in by hand, using the ascii-exported MTL file from the ArchiCAD -> Wavefront obj-conversion.
	The specular color, the ambient, diffuse and specular amounts and the transparency could be copied to the RIB-file.
	I used the "3dto3d-shader", included with 3DWin and saved it with a few changes to "SB_general.sl" so it takes the reflections into account. This was used on the glass and on the window-frames in aluminium.

All the sources for this rendering can also be downloaded (+/-825Kb). The texture-maps are still ignored by the demo.

After I registered 3DWin, I was able to make a new rendering. Now I finally have the textures and material settings converted. Still the textures needed to be converted to TIF.

The default rendering looked better but was washed out because of the lights!

I changed the ambient to 1 instead of 10... Now that was a major difference!

Then I changed the glass-shader, to use reflections. Not very visible, though.

The last step was the radiosity-option:
Option "radiosity" "integer steps" [256]

This last version took +/- 5 minutes to render @ 800x600.
Download bmrtplus.zip (544 KB)

PLUS

	It's worth searching for a conversion solution, because BMRT has a very good renderer (including radiosity) and the RIB-format is supported by many applications.
	3DWin and Polytrans can make a decent translation (so the abandoned ArchiCAD-export isn't such a problem).
	After tweaking the source-file, the results became much better

MIN

	As you can see in the first example, the textures and the lighting from the ArchiCAD 6.0 export didn't survive the conversion. All I got was a flat shading. I believe they made it for "MacRenderman" or so and it's no longer used (the plugin disappeared from version 6.5+).
	Steep learning curve.

More info

	Exluna & BMRT: http://www.exluna.com/products/bmrt
	Pixar & PRMan: http://www.pixar.com
	ArchiCAD2Rad: http://astronomy.swin.edu.au/pbourke/radiance/archicad2rad
	Thomas Baier & 3DWin: http://www.tb-software.com

webmaster

Last Update on 2004-08-18