CGTalk - Keyframing Dynamics Mass

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paulselhi

08-29-2006, 02:35 AM

I can't seem to get this to work..is ita bug ? Can someone try s simple cube mass 0 at frames 0 - 10 and mass 10 a frame 11, it should start to fall but i can't get it to work

edit in fact very little works in xpresso with dynamics, the port for "on" on the rbc tag of an object does nothing, shame because otherwise i could child a small block to a large block and have an xpresso collision node which kicks in when the large block hits the floor, thus switching on the child rbc and allowing it to "go independant"

Srek

08-29-2006, 06:28 AM

No, this is not possible. The Mass needs to be the same over the whoe duration of the calculation.
I usualy use forcefields to move objects that needs to be animated at one time and reacting dynamicaly at another.
Cheers
Björn

paulselhi

08-29-2006, 07:25 AM

Thanks for the reply bjorn..shame dynamics really needs to be more controlable via xpresso. Still i will continue my, perhaps quixotic , search for a RBD fracture system for a rotating and falling object

paulselhi

08-29-2006, 08:10 AM

Your field idea is interesting, i am having some success, albeit with a very simple large cube holding a small cube test.

I have the large block set to fall with spin, the small block rests on it and is bound by an unlimited newton gravity field set very high, this "glues" the 2 blocks together, and the blocks elasticity is low. i also have a normal gravity for the main fall

On impact with the ground i key the newton to zero thus the glu is broken and the two seperate

Now to see if i can get it to work with irregular shapes

thanks again bjorn

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