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Showing posts from October, 2011

Wire to RBD feedback in DOPs

Normally if a wire is constrained to an RBD, the rbd isn't affected by the wire at all. Which is annoying ... but I had an idea to get it to work. the wire solver can store the internal forces on the geometry. In DOPs I made a point force, the position is set to the position of the constraint and the force is the wire's internal (linear) force. I have put a sopnet in the dopnet to get the wire and the constrained point so I can reference them in the point force. It could be simpler with a python expression to get the position and force directly without going through the sopnet, but this is just a little test...
For multiple attachment points, I think a copy data node could be used to copy the point force data for each constrained point ...
hip file here

Wire to RBD feedback forces from Sam Hancock on Vimeo.

Snapping Wires

Here is a setup that does snapping wires...

Wires are pre-cut and the cuts get constrained together, in DOPs a sop solver removes points from the constraint groups based on how much the edge length is stretched. The tricky part about this is that the groups have to correspond exactly so that the edges get constrained together properly...
In SOPs before the sim, each line gets cut in two with a carve SOP. One side of each cut is put into a group, and the other side in another group. I use these groups in the constraint in DOPs to constrain the cuts together. Also, the points in side 1 of the cuts has a 'partnerPoint' attribute which stores the point number of the point on the other side of the cut. This is so that the groups can be rebuilt later.
In DOPs there is a SOP solver to remove points from the groups. For one side of the cut, the edge length is compared to the rest edge length, if it is longer than a threshold the point is removed from the group. The second group is reb…