Floor constraint - help needed

Coding Python Support
#1

I also posted this ain the Blnder3d forum.

Harkyman or anyone:

Is there a way to apply the floor constraint to an individual bone of a chain so that the root of that bone stops at the floor?

As I understand it, the floor constraint uses the root of the last bone in the armature chain. What I need is to be able to apply the floor constraint to individual bones of the chain rather than the last bone of the chain.

In this case I have the following structure:

a. A leg chain that starts from:

  1. hip bone
  2. thigh bone parented to the hip
  3. calf parented to the thigh
  4. heel parented to the calf
  5. toes, parented to heel
  6. A floor bone (not parented) with the root located a 0,0
  7. The heel is the IKA (Ctrl-I – without target)

The current CVS Blender 2.40 (11-29-05) floor constraint uses the root of the chain. In my rig it’s the hip bone’s root. Therefore, when I move the rig in the –Z axis direction, the root of the chain (Hip) stops at the root of the floor bone. The feet and legs move below the floor.

I want the heel and toe to have a floor constraint so that when I grab a central bone such as the stomach bone, the whole rig follows along. Then when I move it in –Z, the feet stop at the floor and the rest of the bones will adjust accordingly.

Now I’ve been able to accomplish a work-around using an IKA solver null bone at the heel. The null bone (non-parented) has a floor constraint; the calf has the IKA Solver constraint targeting the null bone. While this works, I lose some of the functionality of the new armature system. Furthermore, the heel and toes point below the floor, though this could be adjusted through either key framing the foot to stay straight or applying a rotation action tied to the axis of the calf, it would be a lot smoother and greatly reduce the key framing time to be able to apply the floor constraints to the foot bones.

Here’s the adjusted rig.

http://gallery.mudpuddle.co.nz/albums/Room335/Body_rig_test_with_null_floor_5.blend

#2

Been messing with your file since I got it yesterday. The 2 problems I have with the floor constraint is that 1) it only recognises the base of the bone and 2) it’s overridden if the bone is in an IKChain. With this rendition you can get good looking IK’s and, if you control the Z travel of both the Control and IKA bones, and the space between them, then going thru the floor can be avoided. Hope it helps.

http://blender.isoserv.com/uploads/Body_rig_test_with_null_floor_6.blend

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#3

Fligh %

Thanks. I like your approach to it. For some reason, which is still a mystery to me, I could not get the IKA_left to recognize the plane as the floor. Maybe it was misspelled.

As to the floor constraint, yes that’s exactly what I was saying. I’m hoping Harkyman or someone can be convinced to add maybe another button to the floor constraint where an individual bone of the chain can have the constraint rather than the root of the chain.

I recently purchased the Jeff Lew animation instruction video and I noticed that his rig (In Animation Master) the feet stop at the floor and the rest of the rig adjusts accordingly. It’s seems to me that this feature would be an incredible time saver in key framing. That’s what I’m trying to accomplish.

#4

Unfortunately, constraints can’t break an IK chain. IK chains are above constraints in the evalaution “food chain”, and take precedence over them. That’s just the way it works, as far as I understand.

I’m still working on a good rig with feet constrained by Floor. When I get a nice one, I’ll share it.

#5

OK, I understand the IK chain break dilemma. :frowning: I guess Animation Master must have a differant coding system. I know nothing about coding.

I used the null bone at the heel to stop at the floor. This works decently except that the heel and toes continue to rotate through the floor.

I’ve tried using the copy rotation constraint on the toe that follows a null at the knee (Fligh % suggestion) which helps but gives some strange angles if you bend the leg too much, or like in a walk cycle where the heel of the foot is about to touch the floor. This could be adjusted through key framing a rotation on the knee null bone I suppose. But I’m trying to make a rig that has the least amount of key framing adjustments.

I’m going to experiment again with a foot rotation tied to an action constraint.

I’m looking forward to seeing what you come up with.