growing geometry - self intersection problems

[j00ey]

Hi

 

I wonder if anyone can give me some pointers. I'm trying to set up a system that will take some polygonal geometry as an input and from all unconnected edges will grow new primitives in a direction governed by a number of forces [surface tangent, curl noise, gravity etc]. It's working up to a point already but I'm having problems getting self intersection testing to work smoothly.

 

My method is to test for self intersection at the stage where I calculate the forces and if there is any, scale down the force, and if it's below a certain threshold set it to zero [ie stop growing]. The problem is that the self intersection can happen in a single timestep, rather than intersecting preexisting geometry it can intersect with a neighbouring new prim. It seems somehow I need to generate the next step's geometry, then branch off a timeshift to go back a step and do the intersection testing there.

 

If anyone has experience with this sort of thing, does that sound like a route worth investigating? Or is there some other method I should look into?

 

In case it's relevant, I'm trying to do as much of it as possible in VEX to keep it running fast. Also I've seen similar work where the geometry is remeshed on each frame but instead of doing that [for speed reasons] I'm looping over the prims and checking all the edge lengths and if any of them is greater than a given threshold I subdivide the prim.

 

Thanks for reading...