View Full Version : A slight bounce with dynamics

03-19-2007, 07:47 AM

I'm trying to create a can falling on a surface effect, where the can just falls down onto a plane, slightly bounces and rotates, and then stays static.

I'm playing around with dynamics, and even though I can easily get the can to fall and stay still, I can't seem to get any of the other movement. I tried playing around with the elasticity, and in my viewport it seems like there is a slight rebound, but not in the render...

I looked into the docs, but they are not too explicit about how to achieve this..

Any suggestions or good tutorials out there for that?


Neil V
03-19-2007, 09:51 AM
Shouldn't you be able to achieve this result by going through the sunglasses tutorial in the Tutorial PDF? If I remember correctly this should cover such things as mass, bounce, rotation etc.

Sorry I can't confirm this as I'm currently on a workstation without C4D installed.

Simon Wicker
03-19-2007, 11:56 AM
one thing to remember is that the bounce settings are multiplied together so if you have two objects and set their bounces to 50% the actual bounce is 25% (.5*.5=.25).

this makes it very easy to get into situations where your bounce is miniscule.

cheers, simon w.

03-20-2007, 01:05 AM
Thanks, I actually digged into the Dynamics PDF and found a lot of answers (the R10 manual is really more a reference than a manual...). However there is something I don't understand : what if I want to modify the "natural" dynamics, i.e I would like to give my can a little rotation while it is falling, but have it "magically" stay steady once it has hit the floor instead of "naturally" falling on its side.

It seems like Dynamics will only accept a start value, but no values over time.

Am I right?


Neil V
03-20-2007, 09:15 AM
I'm not really sure as I haven't touched Dynamics for a loooooong time and won't do so until they update it.
Maybe you could keyframe an increase in the Mass of the object so that it falls and rolls over say frames 0-150 or whatever; then boost the Mass up on frame 151 so that it stays where it is. Not sure but might be worth a go.

03-20-2007, 09:19 AM
The unwanted movement is due to increasing rounding errors.
Usualy i would simply use a drag field until the coin is as still as it can get and end the simulation then.

03-21-2007, 12:57 AM
as far as I can remember a starting rotation is only possible yes...but you could try offseting the objects center of mass a bit and then key frame in a wind deformer to push the object a little.

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