It does add a bit to simulation time, but much faster than before. If I tweak the settings a bit and emit from a different object, I could make a tornado out of this pretty easily!
Nice Tobbe 
cool embryo of a tornado!
Hey Tobbe, I’m trying to figure out how to get an orbit like this. What was your Magma setup? So far everything I’ve tried has been unsuccessful. I tried modifying a Krakatoa Flow that Bobo posted which causes particles closest to the center of an object to rotate around faster and the farther they are, the slower. The problem I’m having is that this ends up acting like a standard vortex force and everything ends up exploding out.
I posted a picture of the flow. And the link to the flow is here: http://forums.thinkboxsoftware.com/viewtopic.php?f=22&t=11694
Hey,
I am not using math but rather velocities from PRTs at a given frame. There are a bunch of ways of accomplishing this result, but the easiest would be to set up a pflow system with particles going in a circle, then save it out a single frame where the particles are moving the way you like as a PRT (or the sequence if you want, but I prefer to add variation later). Load it in a PRT Loader and check “keep velocity”. Then do a velocity splat. The centrifugal forces will make the sim fly away so I tend to blend with another force to push the velocities inwards (using an object in the shape I want the tornado to be and use the normals). Hope that helps!
Tobbe
That does! I’m curious how to get a pure orbit too, I’ll post a new topic just for that. But you just highlighted something about Stoke I totally overlooked, which is using PRT forces from existing velocities. I have to say, Stoke really does dig deep into the details. I love it! Thanks Tobbe 
Glad it helped! I haven’t finished this yet but it’s something I started. It was set up really quickly, like within a few hours. The motion is a bit tendril at the moment so that’s something I need to fix when I get back to it. But the power of Stoke is really awesome and it’s so easy to get predictable results fast.
Tobbe
Looks awesome! Can’t wait to see the final render.