it would be great to have some mappers here

i will try to create one... I hope there is a good exporter for blender

Hm... i plan to study blender.
I know autocad good, so i could try something in autocad.

I don't think there is a exporter for autocad
As far as I can see, even for blender, there isn't a good one:
http://www.katsbits.com/htm/tutorials/blender_export_model_to_map_advanced.htm
maybe I'll find a way...
however, it will not be a problem for you to use gtkradiant with the knowledge of Autocad I think (nexuiz/extras/netradiant..)
But radiant give me the impression that it is not that flexible.

If you need a tutorial, have a look at: http://alientrap.org/forum/viewtopic.php?t=3334
helpful and funny

yay,i dont have too much time so for this time good luck guys

tips:
gtk radiant have problem in linux,try netradiant...here are links:
http://archive.getdeb.net/getdeb/ubuntu/jaunty/ne/

gtk radiant page:
http://www.qeradiant.com/cgi-bin/trac.cgi

net radiabt page:
http://dev.alientrap.org/wiki/7