(Cross post on odforce.net)

I am nearly there with this system. I have been able to get the points to run the circuit around the turns as long as i start them from the prim center, but when I switch it to start from random surface points so the points are varied, there seems to be some issues with my calculations.

There are two nodes in the network that are giving me trouble, both are attribute nodes. The first is simply trying to map an attribute that I calculate in a VOP POP to a local variable, something that I shouldn't even have to do, and have used elsewhere in the scene successfully, but this particular variable is being pesky. It will work for a few minutes, but then break without any modification to it. It is being unstable and I am unsure why.

The other is a node that calculates the point at the center of the turn so I can get a turn radius and radial velocity further down the line, but it seems to be grabbing the wrong points and I am struggling with figuring out why. The calculation should work logically, as long as the previous attribute does.

I have turned the two nodes with problems red in the POP network inside the main SOP. Anyone with any explanation for this behavior would be welcome.