Creating a nebula simulation from a photograph

[MirrorSword]

For a College Project I'm thinking about trying to recreate a outer space nebula from a photo and using a gas simulation in Houdini to make it move. I'm wondering if anybody has any ideas on how you would take a picture of a nebula and convert it into a 3D volume. My Idea is to take the picture into photoshop and remove any stars or background objects and then take the image into Houdini and project it onto a plane. Then I could use the painting tools to define the z position and depth of the nebula. Once I have this information I could convert it into a volume and then feed it into a simulation. Also if anyone has any specific information about simulating or rendering a nebula that would be helpful.

below is the reference I'm planning to use.

[pclaes]

How much does it need to animate? If not that much you might get away with warping it rather than simulating.

For generating this exact shape in 3d I would split the volume in different bits. Model it roughly (a revolved surface to start with and then sculpt it) and try to either get the finer detail with a volume shader, or by scattering lots of points with low opacity and perhaps advecting those with curl noise for a few frames.

I would then do a couple of separate fluid sims and merge them in (manually positioning them to get the shape you need).

A few weeks back someone posted a fluid sim warped along a curve which might help you to distort it as well. Again how much does it need to move? Do you plan to go close up/fly through?

[bunker]

I made a simple setup with particles advected by a fluid sim

nebula.hip

[MirrorSword]

Pclases, I hadn't thought of just warping it that is an interesting way to approach it. Why do you think a fluid sim would work better than a gas sim. I had played with both but it seemed like the smoke sim was closer to the look of a nebula because it had a varying density but the problem with it is it seems to diffuse to much.

Buncker, Thanks for the hip file it looks cool. I hadn't thought of having the nebula be particles and advecting them with a simulation.

I've been thinking about it some more and I think my project may be going in a slightly different direction. maybe not based directly off of a photograph. I'll be Ironing out the details this weekend. Anyway thanks for the help guys.

[pclaes]

fluid sims = gas sims (both are CFD), liquids would be more SPH and would indeed not be very appropriate for this stuff.

Advecting particles is a typical thing to do, it will help you get fine tendril like detail - but you'll need a lot of particles to make it work. Search on the forum for "ink" or "millions of particles" if you choose to go down that road. If you are more into fluids (smoke) sims, have a look at upressing and noise at shader level.

The suggestion for warping was more related to the restriction of matching the image, if you don't really need to match it than sim away .