View Full Version : Leg rig. Animated pivot

06 June 2003, 07:56 PM
Constructed a leg rig today, and I thought that an animated pivot for the foot would be nicer than all those nulls ppl use :)

Tell me what you think!

06 June 2003, 08:08 PM
Intersting. Mind explaining how you set it up?

06 June 2003, 08:12 PM
I'll post the scene in a little while. I just want so see if someone can pick it apart 1st :)
There is no magic about it. It works perfect and is so damned simple to set up its amazing!

06 June 2003, 08:50 PM
If I had to guess, I'd say you've got on null in the ankle and all the IK goals are children of it....when you rotate that one the whole foot rotates. I use the same kind of thing, but I've got it written down somewhere what the hierarchy is. No sense cluttering the mind with things that can be looked up.

Facial Deluxe
06 June 2003, 09:07 PM
Amazing, first time I see that kind of setup !

06 June 2003, 11:10 PM
It looks cool, but have you animated a walk cycle with it yet?

I'm seeing a small wiggling of the foot when you slide the pivot. This could pose a problem.

I'm also wondering if it's annoying to keep moving the null to where you want to the rotation point. Having more than one rotation null, located where you know it to be, and with proper proxy objects seems easier to select and manipulate.

It's a cool setup nonetheless... I'm just wondering if it's better for animating a foot than the traditional method.

I think it could be really useful for manipulating hips, though. Just a thought.

Triple G
06 June 2003, 03:30 AM
Looks pretty cool...I'd be interested to know how you set it up. :)

06 June 2003, 03:59 AM
How come the toe bone doesn't remain independent when you pivot the rotation at the toe? Can this setup do that? Like lifting the heel without altering the toe?

06 June 2003, 06:37 AM
Toonshady and Webfox:

I don't do setups that way. After working as an animator for several years now, I appreciate simplicity more.
for example: Say that I have this automatic toe bend thingy, how does it know if the foot have ground contact, or is lifted (middle of a step). Also some setups with lots of nulls gives many many animaition channels working against eachother. So much easier just to have one set of channels, aint it?

Originally posted by toonshady
How come the toe bone doesn't remain independent when you pivot the rotation at the toe? Can this setup do that? Like lifting the heel without altering the toe?

06 June 2003, 07:37 AM
The "fewer channels" argument is definitely in your favor and a very good point. I know that, firsthand.

Your foot still wiggles in the video, though. Have you found a way around that, or does it not show up in animation?

06 June 2003, 07:40 AM
Oh! the wiggling is now just a memory!
It was just me not being too precise about things

That should actually help you pick apart this scene.. Hmm.. wiggling.. Is he trying to compensate for something ;)

I'll post the scene in a few hours btw

06 June 2003, 08:54 AM
I thought computer guys bought flashy cars to compensate for "something."


06 June 2003, 08:56 AM
I don't even own a car :thumbsup:

Well.. this is how I did it:

Leg bones..
Ankle null as IK goal for foot bone. (match goal orientation)
Ankle null parented to pivot null.
Pivot null parented to foot null

frame 0. Pivot null at heel.
frame 10, pivot null at toe. Compensate by moving ankle null back to original place.

Add cyclist to ankle null. Tie it to pivot null.
Now you can move the pivot and the ankle stays put.

Add foot main null.
With follower, tie translate on foot null to foot main null.
with follower, tie rotate on pivot to foot main null.

Now only animate pivot null and foot main null.

06 June 2003, 09:04 AM
And the scene to pick apart:

What I want to add to it is to make it possible to move pivot sideways to allow rotation at edge of foot.

06 June 2003, 09:13 AM
Do a walk cycle, please. Let us know if you like how it responds.

I can't tell if you're going to get weird movements with all the extra position curves of the pivot.

06 June 2003, 09:25 AM
I created a walk cycle. Works perfectly. Easiest toe to heel rotation ever!

06 June 2003, 09:32 AM
That's an interesting setup....It's great to see someone pushing rigging concepts! :applause:

But I'm curious how you're going to handle the toe pointing? In your examples (and in the sample scene, thanks, by the way, for making that available) the toe points with the foot...and I tried parenting a goal to the base foot controller and adding a match parent orientation to the toe with that null, but since the root null rotates, it doesn't do any good, without maybe an expression to counteract that rotation? I didn't put a lot of time into figuring it out, though, maybe you've already got a solve in hand...

I think it's a cool setup, but it requires more effort to animate, it you, I think I value simplicity more...but definitely a cool idea....

06 June 2003, 09:33 AM
Just grab the toe bone and rotate it :)
As easy as it gets.
I will most likely not even use this pivot object that much. I animate everything from the heel. even standing on the toes.

Oh.. just recently I constructed a failsafe Arm IK setup with just one null aswell.. I'll post it later..

06 June 2003, 10:21 AM
D'oh! you're right...that IS as simple as it gets....:)

I'm with you, though...I animate from the heel as well...I usually do add an extra null to rotate from the toe, but rarely use it ...

06 June 2003, 10:35 AM
Excellent Tudor :thumbsup:
Looks like Character Studio Planted Key.
I thought that u used expression for goal compensation movement ...

06 June 2003, 01:09 PM
Just fixed it so it works if you move the pivot sideways aswell :)

Anyone know how you can limit an objects translate as with rotate? That would help me not moving the null too far.

06 June 2003, 01:36 PM
very cool set up, man:thumbsup: thanks for sharing!
I'll be using this set up pretty soon.

07 July 2003, 01:19 AM
Anyone know how you can limit an objects translate as with rotate?

There's a clamp function in the expressions builder.

07 July 2003, 01:36 AM
Very cool, thanks for sharing! :thumbsup:

07 July 2003, 07:40 AM
I'm afraid that only works when limiting and object controlled by another object.. When doing it on the same object you get an infinite loop (I belive)..
But I'll givet it a shot again! thanx :)

Originally posted by webfox
There's a clamp function in the expressions builder.

07 July 2003, 04:50 PM
I have been avoiding the infinite loop problem by using the "Value" variable. "Value" references that channel of the object to which you are applying the expression without creating the loop.

Whenever you create a new expression, "Value" is there in the line. That means that the channel it's applied to is equal to itself. Value + (your expression) is how you'd modify something with expressions that you'd want to animate and still have it be influenced by something else.

At least this is how I've been doing it.

Hope this helps. :thumbsup:

07 July 2003, 05:10 PM
Cool! I got to try that out! :D

07 July 2003, 04:46 PM
I am trying this setup as well, however soon as I add cyclist the ankle null moves with the pivot null now :(

Frame 1: foot/ankle/pivot all at the same place on the Z axis
Frame 10: foot/ankle at same place on z axis, pivot is up where the toes would bend

Soon as I apply cyclist to the ankle null it starts to follow the pivot null

cyclist settings

Z axis
cycle frames 0-10
controler pivot positionZ
range 0 to --85.221
end behavior stop

07 July 2003, 06:49 PM
Hmm.. can't tell why it isn't working.. Try swithich the values for the range..

07 July 2003, 07:06 PM
Is autokey on or off?

07 July 2003, 03:59 PM
auto key was on
I am gonna give it another run through today and see if i was doing something dumb

07 July 2003, 04:43 PM
after deleting my whole character except for one of the legs I finally got this to work. However I am lacking the understanding on how to limit the pivots movement. I tried useing clamp but didnt seem to work right. I can still drag the null past where I want it to go.

Attached is the scene I am messing with.

07 July 2003, 05:47 PM
Check out this thread.. Newer rig that does the whole thing better.

07 July 2003, 06:03 PM
ok I noticed you got rid of cyclist and used some expressions which seem to work better because it locks the ankle in place no matter the x or z movement of the pivot. however I notice a bit of jumping in the ankle null when i move the pivot around. anyway to buffer this so it does do this. Also is there a way to totaly limit the pivot so that it cant go past a cetain position no matter what?

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