This is what I did to make Bricscad V11 work on Oneiric because of the
libGL.so not found error:
1)if not installed already, install ia32-libs package from ubuntu software center
2)install 32 bit Bricscad package downloaded from bricsys
3)download mesa deb package for i386 (at this time: libgl1-mesa-glx_7.11-0ubuntu3_i386.deb) and open with archiver
4)extract libGL.so.1 and libGL.so.1.2 to /opt/bricsys/bricscad/v11/ (extract to your home folder and use sudo nautilus command from a terminal to copy the files in graphical mode..) or simply enter sudo cp libGL.so.1* /opt/bricsys/bricscad/v11/ from terminal.
I hope that somebody will find this useful!