Footstep and Freeform modes both use the same underlying inverse kinematics (IK) to animate the biped skeleton. Footstep gizmos are a method for manipulating sequences of IK keys.
In this lesson, you’ll learn how making changes to the IK keys affects the footsteps.
Set IK Keys to create footsteps:
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Drag the time slider to play the animation.
The biped hops on his right foot. Notice that there is no footstep for the right foot between footsteps 2 and 3.
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In the Key Info rollout on the Motion panel, click Set Planted Key.
The pivot point is displayed in the viewport. If you can't see it, change to Wireframe viewport shading, or navigate the viewport so you can see beneath the heel.
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Click next key to go to frame 48, and then click Set Planted Key.
The pivot point shifts to the toe.
Note that the lowest IK pivot is selected by default for cases where IK is applied to new keys.
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At frame 54, click Set Planted Key.
The biped is moved back to the ground. A footstep is displayed beneath the biped’s foot.
A footstep has been created, because there is now an interval of time where IK is applied between the two planted IK keys. However, if you drag the time slider to play the animation, you will see that the walk still needs work.
Change the duration of footsteps using IK keys:
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On the Dope Sheet tool bar, turn on Edit Keys if it is not on already.
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In the Biped rollout, turn on Footstep Mode to easily locate the track in Dope Sheet.
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Expand the Footsteps track and notice that footstep 3 extends for 15 frames, from frames 45 to frame 60.
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The Dope Sheet editor again displays the Footsteps track.
The duration of the footstep now is 18 frames, from frames 45 to 63.
Remove footsteps using IK keys:
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At frame 45, select the Bip01 R Foot object in the viewport, then set a free key.
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Note: The body vertical position is modified. The biped now floats up into the air at frame 54.
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There is only one IK key left. With no IK interval defined, there is no duration, and therefore no footstep.
The animation could be made more realistic by adding arm movement to the hopping steps, or by creating a freeform period for the hop, then adding poses for a crouch, spring and landing. The point of this lesson, however, has been to demonstrate that footsteps can actually be created or removed by changing the IK keys.
In this tutorial, you learned how to animate a biped using footsteps, and make a biped, walk, run, do flips, jump, and take a fall. You also learned how to add a freeform period to a footstep animation, convert a footstep animation to freeform animation, and change the duration of a footstep animation using IK keys.