Solver either not solving or stuck on frame 0

[Atticus]

Hey everyone, just starting out with Houdini and trying to wrap my head around some effects I can produce, but I've hit a big of a snag when it comes to using a solver SOP on my animated model. 

 

The idea is that the model will be falling through the sky, and whenever a part of his body passes through some cloud, that part of the body will dissolve into cloud as well. So the the cloud points will trigger the body points whenever they get close enough. 

I'm using a solver SOP, having the points in the clouds use a PCFind node to trigger an attribute change in the points in the model. However, I have an issue when choosing the Import style for the solver's Prev_Frame. If I use Fetch Geometry from DOP Network, the model's animation freezes (in and outside of the solver) and nothing can proceed. If I use Transform Input Geometry, the animation resumes, but nothing seems to solve from the previous frame. 

 

I've attached a version of the file that has the some limited success in making the body dissolve, but the points snap back to the falling body as soon as they exit the cloud, and I have no idea how to proceed.

Any clues on how to approach this problem would be greatly appreciated!

CloudDive.zip

[Atticus]

Scratch that, had it solved for me. I hadn't realised that the positions of the geometry had to be told to be updated within the solver. Turns out it was solving with the previous frame just fine the whole time, but it only appeared frozen because it hadn't been told to move.

A quick Wrangle node with inputs of the Prev_frame and Input_1 with the following in the VEXexpression: v@P=point(1, "P", @ptnum); 

After this, everything I was having trouble with was all fixed up and ready for the next stage.