Walking with a cane - walking stick how to rig?

[magilla]

Any suggestions for a simple rigging solution for a char to walk using a stick?

--magilla

[gmask]

I suppose you could just add anothe rbone and parent it to that and use an IK handle.. I think that would be effective. Although if the stick leaves the hand.. maybe you would parent a locator to the hand so that you could use a point contraint on the end of the cane.. this way if you animate the influence of the cotnraint the cane can leave the hand and maybe use a aim contraint to to point the cane as it is being walked.

[nonquad]

maybe you would parent a locator to the hand so that you could use a point contraint on the end of the cane..

Hmm. Only thing is, could you do that and still keep the cane in control? IE if one end of the cane is touching the ground and the other end is in the palm of the hand, then the cane is not going to be constrained to the hand; it would have to be vice versa. The cane would have to be the control object, rather like an IK foot... with the hand stapled to the end of it. So that when you rotate the tip of the cane on the ground, the hand sticks to the top end of it.

You could do this by grouping the IK hand, and using constraints to attach that group to either the world or the cane (switchable).

Or, alternately, you can put the IK hand and the cane in a group, and animate that group when the two objects are connected. I've actually done it much like this before in a similar situation, and got good results.

The only thing is, either way you will need to do some counteranimation when control changes. With the constraint switch you would need to counteranimate so that the objects don't move during the switch.
Whereas if you use a group for both, you will need to animate the rotate pivot point of that group to the correct position each time the cane is planted on the ground. (and, likewise, move the rotate pivot more towards the cane's center of mass when it is picked up, for more convenient rotation control)

In reality it's not all that bad. Just use stepped keys when animating the pivot point, and only do it when necessary, or things start to go real funny. Also note that you have to make the pivot keyable (channel control)

also: don't put motion trails on anything dependant on an object with keyed pivot. When such a motion trail is evaluated, maya instantly crashes to desktop, without even an error message. Or at least it did in 4.0. It was my favorite way to crash the program =p like black magic.

[magilla]

ok - I tried a reverse ik foot like setup last night - it kind of worked but you have the same problem of the hand being moved away from the pivot when you rotate from the base of the cane - much like the rotate fom toe moving the ankle away fromits pivot - no biggy.

I thought I'd try the animating pivot - cos that seems much simpler - but for the life of me I can't get the pivot to move back to its origin without moving the object - I must be animating the wrong pivot - Is it the rotatePivot or the rotatePivottranslate or the rotatePivotaxis??????????????? aaaaaargh &(

--experimenting magilla

[nonquad]

you need to key the rotatepivot and the rotatepivottranslate. keying the scalepivot too would be safe, but probably unnecessary.

always key them at the same time, and keep those keys stepped, and you should be safe.

here's an example
http://mywebpages.comcast.net/jstewart912/pivkey.mb

in this example I animated the sphere first, then when the sphere, ie 'hand' lands on the cane, I start animating the cane group, rotating around its pivot at the origin. Then when the cane is picked up, I move the pivot and started animating the group around its new pivot.
To move the pivot during animation, the process is:
key the pivot (rotatePivot and rotatePivotTranslate),
step forward one frame in time,
use the 'insert' key to get into move pivot mode,
move the pivot to its new location,
key the pivot info in its new location.

I think you could probably do interpolated (smooth) pivot animation over time, if you followed some conventions to keep things tight; ie always key the rotatePivot and rotatePivotTranslate at the same time, and always with the same tangent type.

But using stepped keys is an easier way to keep things safe.

Also: side note, maya isn't very good about updating the channel box for the pivot info. Just move it and key it. Sometimes the change won't appear until you change frames, but it's there.

[magilla]

and the veil is lifted from my eyes.....

I wasn't keying both the pivot and pivot translate - works like a charm.

thank you

--magilla

[nonquad]

good luck on the animation!

[magilla]

I notice I don't need to "insert" to move the pivot - although I use a script to select the pivot.

select -r nurbsSphere.rotatePivot ;

I guess it's "six of one..."

cheers

--magilla