CGTalk - Coin rig? Swivel

JookBoxer

08-29-2009, 01:37 AM

You know when you drop a coin and it swivels around the edge.

How would you rig it? I can't use dynamics for this.

I've tried grouping objects inside of objects and having the child object move on various axis of the parent object via an expression. I had some minor sucess with that. But it was very hard to control motion.

It'd be great if there was a way to rotate the swivel point so that I could control where the coin was touching the ground and how high the opposite edge was from the ground.

Any help would be much appreciated. Thanks!

JookBoxer

08-29-2009, 08:19 AM

I got something else sort of working.

Two ways of using an aim constraint.

Make a cylinder Facing up on Y. A null. aim constrain the cylinder to the null with settings of x and z. Then animate the y rotation on the cylinder. The amount of swivel can be adjusted by moving the null up and down on the y axis. This one rotates as it swivels.

Method two.

Make cylinder. Two nulls. One null child of the other. Move the parent up the coin. Aim constrain the cylinder to the child null using all axis so that the top of the coin is facing the child null that is above it. Make sure the cylinder and the parent are on the same xz plane. Move the child off to the side. Rotate the parent. The coin swivels without rotating.

Btw.. I don't like either of these methods... So if somoene has a better way........

Also. Anyone have a way to make a cube swivel?

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08-29-2009, 08:19 AM

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