Background: what I'm trying to do is to set the “active” status of RBDFracture pieces based on their world space positions. I.e., so that I can keyframe an overall animation, then have the pieces turn dynamic when they get near the ground.

The test setup: I have a box that's copied to the points of a sphere. The whole thing is keyframed, and also made into an RBDFracture. The RBDFracture has its Active parameter keyframed to turn on at frame 10.

The problem: the Position “p” and “t” data on each fracture piece don't contain the actual position of the RBD piece when the piece is not active. Load up the attached sample file, and watch the position of “circle_object1”. After frame 10, it tracks properly, but before frame 10 it just follows the parent object.

The solution? I'm guessing it involves getting the world space position of each fracture group from *outside* the DOPnet, but I'm not quite sure how to do it. (Bit of a houdini n00b.) Note that eventually, I want to acess this info in an expression on the RBDKeyActive node (I.e. from *inside* the DOPnet), rather than from the circle object. Also note that I'll eventually be doing this with many, many pieces - which is why I don't want to create an RBDKeyActive node for each piece, or enter the keyframes by hand.