making a simple footroll?

#1

Hey Guys

Using the motionbuilder rig is completely different to what im used to in maya and i cant figure out how to roll the foot like you would need to do during a walk cycle. If I have the floor contact on the foot active and rotate the ankle joing the foot does begin to roll, but the foot also moves back.

Is there a simple way to set a foot roll up that im not familiar with?

Thanks

#2

I know if you lock the Transition of the ankle in the control panel it will cut down on the movement of the ankle joint. But your foot still tries to follow proper physics, so if you rotate the ankle too much or its to close to the ground, it will shift the position of the ankle so the bones don’t bend and break.

Hope this helps

#3

you can setup an inverseFoot in MB too - you can find a tut on the alias website (bronze membership). I did it but found it very complicated for what MB gives you.

tip: as i’m using MotionBuilder-Shortcuts (althoug I’m using Maya for modelling) i often press W (for translate in maya) which blocks your translation and E (rot in maya) block your rotation in MB. with these shortcuts it’s easy to get fast.

greets

#4

i have the exact same problem, but i am using fullbody ik in maya. i rotate the foot effector and the foot moves back, so frustrating. how do you manage this?

krolichka

#5

Ok there might be a much better way of doing it, but here’s how we handle reverse foot controls at work. This is built to work with pre-existing motion, so if you’re starting without any animation you can cut out alot of these steps (I think at least, i’ve never had call to do it).

  1. Create an auxiliary effector at the ankle.
  2. Create a parent/child constraint and constrain the aux effector to the ankle IK effector.
  3. Select the aux effector and do Animation > Plot Selected (All Properties).
  4. Turn off the parent/child constraint.
  5. Turn the Reach R and Reach T sliders on the ankle IK effector (make sure it’s the IK effector and not the Aux Effector), down to 0.

What you’ve done so far is to transfer the animation information from the ankle to an aux effector and made it so that it follows the aux effector and not the ankle IK effector.

  1. Create an aux effector at the foot.
  2. Snap constrain the foot aux effector to the ankle aux effector with a parent child constraint (you might as well use the one we created in step 2 since we’re not using it anymore). Make sure that you use snap so that the foot aux effector maintains it’s relative position/rotation.
  3. Select the foot aux effector and do Animation > Plot Selected (All Properties).
  4. Turn off the parent/child constraint.
  5. Turn the Reach R and Reach T sliders on the foot IK effector (make sure it’s the IK effector and not the Aux Effector), down to 0 (if they’re not already off).

You’ve now transferred the animation information from the ankle aux effector to the foot aux effector, maintaining it’s relative position and rotation, and made it so that the foot follows the foot aux effector and not the foot IK effector.

  1. Ensuring that you turned the constraint off in part 9, swap the foot aux effector and the ankle aux effector in the parent/child constraint so that the ankle is constrained to the foot and turn on the constraint using Snap.
  2. Go into character settings and turn on floor contacts.

That should about do it. The ankle should now follow any translations and rotations that you make to the foot aux effector. It also means that you can plant feet alot easier by deleting translation keys on the foot aux effector, copying/pasting keys across the section that you want planting, and switching to a linear interpolation. The bonus is that since this is all using aux effectors you can happily delete those keys without destroying any motion data from the original animation. If you don’t like the changes you made just delete the auxiliary effectors, turn the Reach sliders back to where they were and you’ll revert back to your original animation. Once you’re done with this setup just select the foot and ankle IK effectors, do Animation > Plot Selected (All Properties), and then delete the aux effectors.

I know it might seem quite long winded to set the feet up like this, but it’s the same every time so if you know python (or know someone who does), there’s no reason why you can’t script the whole sequence. Also, if you’re animating from scratch then you don’t have to bother ploting the existing animation onto the aux effectors, so you only have to do steps 1, 5, 6, 10, 11 and 12.

If anyone has a better way of doing this sort of thing then do post cause this method is longwinded if you don’t script it, so i’d love to hear alternatives.

#6

okey, thats something i cant do in Maya Fullbody IK then…but can i add a reverse foot control to my Fullbody IK in maya. Anyone know how to add that, and will that solve my problem?

Krolichka

#7

You’ll probably have more luck asking that in the Maya forum.

#8

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