If anyone can help me, I would greatly appreciate it. I'm trying to get an expression so that I can have the motion of a particle system take the shape of a spiral. So that the circular motion will come around and get smaller onto itself. Anyone have some ideas?

Thanks.

You must use something like frame number or time. Say radius -= $F * scale_factor
Hope this help.

Hey Guys,

You need to define the equations for x,y,z you can do a curve that will be modified by these three formulas for each axis. They have a tutorial on a on this in the 3D buzz videos in the advanced section that you can only get to if you are in the second section of the 3D Buzz course. However this does not have the curve getting tighter and tighter toward the bottom. This can be taken care of by modifying the equations.

Cheers,
Nate Nesler

P.S. I will see if I can't mess with it. You don't have to write an expression for the frames because you can animate the birthing of the particles as you animate follow the curve path downward.

MatrixNAN, in the Sage's case radius is a function from time (or from frame).