Generally, I agree with Malenfant, unless there are special symmetries and/or universal features involved.
Evidence for an axial symmetry of the density distributions along with universal features of the respective (axially rotated) 2d density in case of
bipolar planetary nebulae have been convincingly discussed in the thesis and subsequent scientific publications of the people from the German MaxPlanck institute etc:
http://www.mpi-sb.mpg.de/~magnor/civr.html
http://www.mpi-sb.mpg.de/~magnor/public ... tvcg05.pdf
http://www.uni-weimar.de/~hildebr2/download/thesis.pdf
See also my respective discussions here:
http://www.celestiaproject.net/forum/viewtopic ... c&start=15
The main point was that in a computer rendering comparison with a number of such planetaries visible in different orientations from Earth such an axial symmetry and rather universal features could be deduced. The familiar great diversity of appearances of such planetaries was demonstrated to be largely due to the different projections/orientations they subtend as seen from Earth.
In case your nebula falls into or is related to this class of planetaries, perhaps similar arguments could be used about its 3d structure.
Bye Fridger