Running feet scene 2

In this scene a woman in high heels runs across a stylized hill.

Export the woman from MakeHuman as an mhx file and import her into Blender. We immediately notice that the boots look weird.

feet-310-init-pose

The reason is that the foot is in rest position. However, a foot inside a high-heel boot is not resting; rather, the woman should be standing on her toes inside the boot. Pose the feet correctly.

feet-320-pose-feet

If we intend to use inverse kinematics, the IK feet must also be posed. The easiest way is to use the snapping tools available under the MHX FK/IK Switch panel in the UI shelf to the right of the viewport. The MHX panels are available when the MHX importer add-on is enabled.

feet-330-pose-ik

Press the Snap L IK and Snap R IK buttons at the bottom of this panel. The legs are now controlled by IK, as indicated by the buttons at the top. The IK bones become visible and the FK bones are hidden.

feet-340-current2rest

We now want to apply the current pose as rest pose. There is a standard tool to do this, but that tool will not modify the meshes using this armature properly. Instead we open the MakeWalk: Utilities panel (this is the last MakeWalk panel in the tools shelf) and press Current Pose => Rest Pose. The rest pose has now been changed.

feet-350-new-rest-pose

In the MHX Layers panel in the UI shelf, enable the Tweak layer (bone layer 10) and disable all other bone layers.Each foot has three marker bones which inform MakeWalk about the location of toe tip, the ball and the heel. The marker bones are placed roughly correctly by default, but since the rest pose has been changed they are now in incorrect positions.

feet-360-markers

Tab into edit mode and place the marker bones correctly. Only the location of the bone heads matter; The marker bones are used for keeping the feet above a floor. The Keep Feet Above Floor will work even if the armature does not have marker bones, but not so well.

feet-370-markers

Now we are ready to create the animation. The first steps are the same as in the previous chapter. Load and retarget the bvh file, loop the animation between frames 7 and 29, and repeat the animation 10 times.

The woman will run across a stylized hill. The hill mesh can be used to keep her feet above the first, flat part of the ground, but it is of no help when it comes to the slope. This is because the MakeWalk tool keeps feet above the object location. Moreover, ”above” means that the z coordinate in the object’s local coordinate system is positive. Since the object center is located on global z = 0, and the local z axis coincides with the global z axis, the woman will keep running above global z = 0.

feet-380-hill

We can still use MakeWalk to keep her feet above the slope. Add a new helper plane and rotate it in object space so it coincides with the up-slope of the ground mesh. The local coordinate system is centered on the plane and the local z axis is perpendicular to it, which are the necessary requirements (error in picture).

feet-390-multiple-floors

Goto the first frame where a foot should rest on the slope, namely frame 25. Delete all old time markers and create a new one here. The scrub the time slider until the character is some distance past the end of the slope and create another tíme marker. Since it takes more time to run uphill, the character should be well past the projection of the slope end at this point. More exactly, the line from the slope end to the foot should form a right angle with the slope.

feet-400-uphill1

With the helper plane and a bone selected, press Keep Feet Above Floor. The woman starts running upwards, keeping her feet on the slope. Repeat the procedure for the other parts of the hill by adding addional helper planes. In the final animation, all helper planes are placed on a disabled layer and the original ground mesh is made visible.

feet-410-uphill2

In this case it turned out that keeping the FK feet above the planes was better than the IK feet. It also matters how far below the plane the feet are initially, because it affects whether the hips are lifted when both feet are in the air. It is usually best to start with the feet as little below the floor as possible, while they must not float above the plane anywhere where they should be planted.

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