Parent A Character Rig To Moving Vehicles/objects

[loganb]

Can somebody explain why this happens?

Say I have a character, fully rigged and ready to animate, But I need to animate them standing on a bobbing boat or in a rocking train car, or dangling from a parachute or some other kind of similar 'parented' motion.

To me, the simplest solution ought to be : parent the character's root node under the boat/train car/parachute, and animate the parent rig. The character should follow the motion of the object it's parented to, right?

However, whenever I try something like that, the inevitable result is that some bits of character geometry translate excessively (or too little) compared to the parent object's motion. wrist watches fly off the arm, eyeballs float out of the sockets, etc.

what's going on? how can I achieve the effect I want without this unwanted extra motion?
how do animators typically achieve this?

[gmask]

well in some cases what you describe might be the result of double transformations. For example a piece of geometry that has been skinned cannot also be grouped under a parent object that is also being transformed. This will cause the geometry to fly away from the joint it was skinned to.

To accommodate what you need to do there should be a parent node that the root and any controllers are all parented to but not the geometry.

It is also common to have a world node which has the above node and the geometry parented to it but it is never transformed and is simply there as a container of sorts so that you have only one tree in the hierarchy view.

[loganb]

Thanks, gmask...i think the reasons behind my problem are starting to sink in. It seems my mistake hgas always been to group the geo and the rig under the controlling object/vehicle.

I've had problems with double transforms before...I'm usually dealing with character rigs handed to me by the client, so the actual structure I must deal with varies...I guess I'm a little surprised that bound geometry still inherits transforms from anything besides the skeleton...doesn't seem useful...

ah well. At least I know whats going on now.

[porcupine]

Hi. would be better group itself the master control of the character, renaming it for example "character_pos", then select your transform node of driving object and ctrl-select the previous group, and use the parent constraint.
Hope this is helpful, bye