This section applies to both inactive and active footsteps. It describes the mechanics of editing footsteps in Track View. It does not, however, discuss adaptation, what happens to the biped's keyframes when you change the timing of the biped's active footsteps. See Adapting Biped Keys to Footstep Edits for a discussion of adaptation.
Footsteps have their own special display in Track View. To see footstep display, expand the objects branch of the biped and the parameters branch of Footsteps.
Footsteps in Track View
The left leg's footsteps are blue and the right leg's footsteps are green. Inactive footsteps are more saturated values of blue and green, while active footsteps are pale blue and green. The left edge of each footstep block indicates when the foot touches the ground and the right edge indicates the last frame during which the footstep is on the ground. The space between footsteps indicates the amount of time the foot is off the ground in between footsteps.
You can change the length or spacing of footsteps in Track View to change their timing.
To select a footstep
Click near the center of the footstep's area.
The footstep's border turns white to indicate it's selected.
To select multiple footsteps, do one of the following
Click to select a footstep, and then use CTRL+click near the center of other footsteps to add them to the selection set.
Drag in the footstep track.
Dragging creates a selection box that selects each footstep it touches.
To move footsteps in the time sequence
Drag selected footsteps forward or backward.
To change the duration of a footstep
Click the left or right edge of a footstep.
In addition to a white border, a small white dot appears to indicate the border is adjustable.
Drag to make the footstep longer or shorter.
You can adjust a selection of multiple footsteps this way.
You can also adjust any combination of left edge, right edge, and center selections. Dragging in Track View adjusts any combination of edge or center selection.
Right-click the footstep track to display the Footstep Mode dialog, described in Footstep Mode Dialog.
This section does not discuss restrictions relating to adapting keys to changes made in Track view to the footstep track. See Adapting Biped Keys to Footstep Edits for this information.
There must be at least one frame in-between any two sequential footsteps on the same side (left/right).
Footsteps cannot appear in negative frames.
Every footstep must be at least two frames long.
If you violate these restrictions when performing any operation in Track View, upon mouse up, Biped restores the footstep track to the state it was in before the change was attempted.
Also, if you make a change that causes two footsteps on the same side (right/left) to overlap, or moves a footstep completely in front of or past another one on the same side, upon mouse up Biped restores the footstep track to the state it was in before the change was attempted.
Below is a list of operations for the footstep track in Track View that either have not been implemented, do not work as expected, or should not be used at all.
Add Keys does nothing.
Cloning footsteps in Track View does nothing.
Align Keys does not work correctly.
Warning: Do not use Align Keys for footsteps.
Reduce Keys does nothing.
Reverse Time does nothing.
Cut/Copy/Paste do nothing.
See Splicing Biped Motion for how to copy and paste footsteps.
Delete Time does nothing.
It does not make sense to delete time in the footstep track. Delete selected footsteps instead, or use the Track View Edit Keys mode Delete Keys button.
There is no function curve for the footstep track, so function curve editing is not available.
If you want to scale a biped's animation, you can either adjust the footstep track's range bar, or use the Scale Time button in Edit Time mode. These two methods will scale both the time and duration of the footsteps. If you use the Scale Keys button in Edit Keys mode, the start time, but not the duration of the footsteps will scale. This is typically not desirable.
Warning: Do not use the Re-scale Time option in 3DS MAX's Time Configuration dialog. If you must use this, you'll have to jiggle the footstep track's range bar in Track View immediately afterwards to get the rest of the biped's tracks to adapt to the scaled footstep track. Even so, there might still be errors, so this is not recommended.
Warning: Since Biped does some internal quantization, it is strongly recommended to leave on the Snap Frames button in Track View when editing any biped track.