I need to animate a “Mobile”. The attached image shows the basic Mobile without any elements attached to the stems ends. I want to have this object slowly spin in place while each individual stem also spins. Thought I could use “Pin Constraints” but all the individual stems begin separating as the animation proceeds. How do I get all the individual stems to pivot at their joints simultaneously.

mtcgs

Sorry, missed the attachment. Here it is.

mtcgs

	Attachment

Hi there,

Hope I’m understanding your question correctly.

You can try placing the joints a each pivoting location and rotate the attachments based on it’s location.

Also, you might have to ‘manually’ rotate each Joint Orientation to be pointing in the right direction.

Parent each to each other upwards towards each chain after you’ve made sure the joints are orientated.

This is a fun thing to do using rigid body dynamics and pin constraints.  Make all your armatures and hangy-things into rigid bodies and connect them to a gravity field, then pin constrain them all together.  You’ll have to move the centers of the pin constraints so they hang from the correct places.  Use a nail constraint at the very top.  You have to go in and adjust the mass of each object so it balances; you can prevent wild spinning by adjusting the damping attribute of the rigid bodies. 

If your hanging objects are very complex, consider using spheres instead.  You can point and orient constrain the objects to the spheres, then hide the spheres.  Simpler calculations that way; cleaner animation.

Once it’s done, put a turbulence or a wind field in the scene, and let it play.  You can bake out the keys afterward.  Let me know if this is of interest to you, and if you need more info on how to set it up.