Noob questions: Transparency & Stars & Nebulas, Oh My!

I’m attempting to dive into some astronomy sims, but I’ve been away from Blender for a number of months. I’m currently using 2.43.

  1. I’ve got a warped plane that I’d like to make semi-transparent to represent a shock wave traveling through space. I’ve given the plane a color, some emit, and I think I’ve got the ray transparency set right. I’m using background stars for context.

When I use Z-trans, the plane is transparent and I can see the stars through it. If I turn on Ray Transp, the alpha appears correct and the color of the world color passes through but the stars don’t. Is this a feature or a bug? Any way to work around it?

Here’s the blend file: http://www.healymonsters.org/public/shock-test.blend

  1. I’m hoping to build a star-forming region animation in the future. But I’m at a loss on how to achieve the appearance of the “glowing blue wisps”:

http://hubblesite.org/gallery/album/nebula_collection/pr1995044b/

I could use particles and haloes for the wisps from the top of the cloud. A second set of particle-haloes could be used for the brownish-yellow layer of glowing gas.

I’m sure I could get the appearance just right for a static image or a simple animation showing a minor change of perspective. But my goal with the model would be to fly in to show the small-scale features at the top of the cloud (the stars forming in some of the little clumps of gas jutting out). I fear a “particle-halo” solution would look lousy as the camera got closer to the cloud and the particles. You would be able to see the individual particle haloes instead of a smooth distribution of glowing gas.

Does anyone have some alternate solutions to modelling of this type?

Perhaps a trick with a mesh volume that would provide some thickness to achieve this kind of glowing gas layer? Combined with a color ramp or texture?

Could a bump map or other “trick” give the illusion of the wisps and the thickness of the glowing gas layer?

(I hope this description is coming across as clear. I’m purposefully avoiding terms like “photoevaporation” and “ionization structure”. I’m an astronomer by trade, not a modeler.)

I’d be very grateful for any suggestions!

I’m most interested in an answer to my first question.

Has anyone had experience with stars and ray transparency?