RBD - 'active' attribute and glue constraints not working together

[DeeLan]

Hey Guys,

I've got a really annoying problem with RBDs at the moment. I've attached a scene for reference (It may take a little long to load as all the caching is disabled. Also sorry if it looks weird. I've been playing around with keep everything from fracturing to simulation in the one network. Everything we need to work with is right at the bottom in the Yellow backdrop.).

So I've got a setup with packed prims and glue constraints (which as far as I can tell is fairly standard). If all my pieces have their "Active" attribute set to 1, everything works as expected. However, if I set some of to have an 'active' attribute of 0 (I've done this in a weird way earlier in the node tree, but I've tried this with multiple different methods and they all yield the same result), nothing moves until either an object collides with it, or I start deleting the glue constraints, and even then I can get some weird results if the glue strength is 0. 

To illustrate this, I've given my constraints a strength value of 0. What if expect is that all the active pieces will fall straight down, and the inactive pieces will stay where they are. However, if you hit play, nothing moves. If you jump into the dopnet "RBD SIMULATION", and then disable the 'constraint network' dop, then it acts exactly as I expect it to (considering that there is no strength in the glue). Alternatively, leaving the 'constraint network' dop enabled, and also enabling the "ALL ACTIVE" sop (colored blue), then it also acts you would expected for a network where every piece is active.

I don't understand why, but having even one piece with 'active' set to zero, and a constraint network attached, effectively yields the result as if everything was disabled. I'm just confused because it doesn't seem to be acting the way I think it should. Is this a case of "thats just how it is" or have I set my network up wrong?

Controlling_Fractures_Problem.hipnc

[DennisSchmidt]

As you described, glue constraints will hold together until deleted or collision. A force breaking on glue constraints does not work. If you want to use forces you would have to use the cone twist or similar constraints. So your file looks fine to me. Setting the active value also looks correct.
I found a file from an older post I made where the conetwist and the active value was used. Check it out to better understand and see one way of how to set it up.

Hope it helps.
Dennis

active_with_constraint_v01.hipnc