Finally, I was starting work with IM and have some questions now.  My main idea was to create an orchestral space, with different positions for different section.  As a base, i was using the "Theatre" model.

First, I'l try to create separate "mono" files, so that I can ssign the instruments in PS to these channels and mix it to the final result, with panning to amplify position effects.

But I always get stereo files out of IM.  Is it true?

Then, I used stereo reveivers and various position renderings.
My feeling is, that the room always sounds "simple", i.e.  it sounds a little bit average and missing the subtle effects.  I would guess this comes out of the 2D approach.

Would there big big difference, if it would be rendered in 3D?

I used 250.000 rays per emitter.  How close to "reality" is your raytracing algorithm?

Is there a guideline for using "sustain" as height?  When I set the damping of the AIR to 0 db, it sounds like a large hall, with a lot of reverb.

About the materials: Where do you get the absorbtion and reflection paramaeters from?  Just by guessing or by measurement?

Lots of questions, sorry for that: experimenting with IM makes me think more and more about rooms and accoustics ;-)

Thanks
hs

WAV file format you get from IM depends on channel assignments of recepting walls.  You will have to assign them all to Left to get mono files.

IM is mainly an artistic tool - you do not have to think about how real the reverb is, because 2D is in no way 'real' - only an approximation.  That's why I cannot give any realistic suggestions.