question about matching foot orientation

Retired Products Animate General Discussion
1

Hi-- this has the potential to be a dumb question but here goes :slight_smile: :

There’s a leg chain made with the hierarchy: femur–>tibia–>foot

and I’ve been animating it with IK-- nailing the foot “joint” to the ground and locking the foot’s orientation to keep it firmly in place while the rest of the body animates above ( tibia, femur, hips, upper body, etc ).

However, I messed up a couple times and the foot’s orientation changes-- pivoting slightly off the ground.

What’s the best way to fix the foot’s orientation to match its appearance in the previous poses? ( keeping in mind that its parent, the tibia, is animating )

I could match the foot’s orientation visually, just transforming it by hand until it’s correct… but I hope there’s a copy-paste sort of solution.

Copy-pasting the previous foot keyframes directly, though, won’t work because the transform values are relative to its parent ( tibia, which is animating ).

Any ideas? ( is there something I’m missing in Paste Special? is there a world space I can switch into temporarily? )

Thanks!
–Ross



2

You might need to apply “IK Constraints”… to your leg…
Check out the following video demonstrations:
http://www.nolanscott.co.nz/Gallery/ik_constraints_1.html
http://www.nolanscott.co.nz/Gallery/ik_constraints_2.html
(no sound, it’s all fairly simple and straightforward)

Regards
Nolan

3

Thanks Nolan-- I actually watched some of your video tuts even before this-- really helped me along with the IK stuff.

I could be wrong, but I think my question is a slightly different problem–

Here’s a different situation but the same question rephrased:

Let’s say there’s a character animation that’s 200 frames long. I’m just about to call it final when I realize I’d be much happier if the foot position/orientation on frame 180 was visually the same as the foot on frame 20 ( and, for the sake of the example, the pose on frame 20 is completely different than the pose initially on frame 180 )

– What’s the best way to match the frame 180 foot to the frame 20 foot? ( and again, the foot is a child of a leg joint chain )

Thanks again,
–Ross

4

Open the Coordinates and Control Points Panel…
With the Transform Tool select your foot…
Check the X, Y, Z Position / Rotation Angle of your foot at those keyframes…
If applicable, apply the same values…

It might be appropriate to apply the same Position / Rotation values down the hierarchy.
Start first with the Femur, then Tibia, then Foot…

Regards
Nolan

5

oops, sorry Nolan-- one more detail I forgot to include: is it possible to get the 2 feet to match ( the situation described in my previous post ) without affecting the transformations of the foot’s parents ( tibia, femur )?

( accomplishing this while keeping the leg joints hierarchy intact )

–So the foot on frame 180 is put into the exact same position, orientation as the foot at frame 20-- and the tibia, femur on frame 180 remain completely unchanged during this process.

( I assume this kind of functionality can be created with scripting if it isn’t built into the software already – take the foot’s local transforms on frame 20, work up the joint chain converting those local transforms into each successive parent’s local space until you have the foot’s position,orientation, etc in world space-- and then reverse the process to get the local transform values needed for the foot on frame 180. )

This question is really a minor concern, but I would feel better understanding how to solve it as quickly as possible-- over projects, seconds here and there can add up quickly and all that.

Anyways, if anyone has any ideas on this, I’d be thrilled to hear them.
Thanks again,
–Ross

6

Thanks Lilly-- yep, using the transform tool to match the foot works well for the once-in-awhile mistakes I was making.

Probably I’ll just start a project and see if mass edits of this type are ever really needed-- then maybe do a script if so.

Thanks again,
–Ross

7

Hmm I think this is a bit of a tricky question, because when you nail the foot down, basically what it does is it figures out what the angles need to be on the parent joints as well as the foot in order to keep the foot in the same position. So if your whole leg is in the same position, you could simply copy and paste the keys from the whole leg. But if the leg is in a different position, and you want just the foot to be in the same spot, you can’t copy and paste because you’ll get the wrong result.

I don’t think there’s any way to retroactively apply a nail. I suppose you might be able to write a script to do this, however it would require some careful thought. You’d probably be faster to just turn on the onion skin and reposition the foot. You could lock your tibia and femur, or simply use your transform tool on just the foot.

~Lilly

~Lilly