Tutorial 3: Animating a Biped with Footsteps

Lesson 2: Modifying Footsteps

The footsteps you've worked with so far gave the biped a default walk. In this lesson, you'll learn how to copy and paste biped motion to extend an animation.


Extending the walk

  1. Select the biped.

  2. On the Motion panel, on the General rollout, turn on Footstep Mode.

    The Footsteps sub-object level is activated, and only the footsteps can be selected.

  3. Right-click to activate the Top viewport, then click the Min/Max button to maximize the viewport.

  4. Using Select and Move, region-select footsteps three through seven.

  5. On the Footstep Operations rollout, click Copy Footsteps to place the selected footsteps into the footstep buffer.

  6. Click Paste Footsteps to paste them in the viewport.

  7. The new footsteps appear next to the biped's current footsteps.

    Tip: If you have Transform gizmo on, use the minus key (-) to shrink the Transform gizmo, so it doesn't cover up the footsteps.

    Size the Transform gizmo

  8. Move the new footsteps (they move as a set) so the first footstep of the new set is over footstep 7 of the original set. When footstep 7 of the original set turns red, release the mouse button.

    Footsteps from the original motion are inserted. Now there are 11 footsteps visible.

  9. Press W to display four viewports.

  10. To display the entire animation in the Perspective viewport, zoom out and use Arc Rotate and Pan to adjust your view until the biped and all 11 steps are visible.

  11. With the Perspective viewport active, play the animation.

    Since you are still in Footstep mode, the Motion panel is available. This is a good time to save your mywalk.bip file.

Scaling the walk

  1. Make sure Footstep mode is active.

  2. In the Top viewport, region-select all the footsteps.

  3. On the Footstep Operations rollout, clear Length, and leave Width selected.

  4. Set Scale = 2.0 to double the spacing between the left and right footsteps.

  5. Play the animation.

  6. Set Scale to 0.25 to reduce the spacing between the left and right footsteps to half of the original scaling (one-quarter the current setting).

    If you hadn't previously doubled this parameter, a setting of 0.5 would have scaled the width by 50%.

    Now the biped puts one foot in front of the next.

    Use Scale Width and Length to adjust the footsteps if your characters have big feet.

    Scale the width between the steps.

  7. Play the animation.

Bending the walk

  1. In the Top viewport, select all the footsteps from 7 on.

  2. On the Footstep Operations rollout, set Bend to 11.0 to bend the footsteps to the left, beginning at footstep 7.

  3. Play the animation.

    Bend selected footsteps

Walking on uneven terrain

You can raise and rotate the footsteps footprints can be d to create the illusion of walking on uneven terrain.

  1. Make sure that Footstep mode is still on.

  2. Maximize the Perspective viewport.

  3. Use Select and rotate to select all the footsteps from 4 on.

  4. Use the transform gizmo arrows to rotate the selected footsteps approximately -8 degrees about the X axis so the footsteps go up a hill.

  5. Select footsteps 8 through 11.

  6. Rotate the selected footsteps about the X axis approximately 21 degrees, so that the footsteps go back down the hill.

  7. Play the animation.

    Walking on uneven terrain by raising and rotating footsteps

    You can also create footsteps on uneven terrain by turning on AutoGrid and then setting the footsteps one by one using Create Footsteps (at current frame). You can use mouse and keyboard shortcuts to move over the terrain as you place the footsteps.

Adding a jump

If there is a period of time during a footstep animation when neither foot is on the ground, it will be interpreted as a jump. There are several different ways to create a jumping animation. In this lesson you'll move footstep keys in Track View to make the jump.


Moving Footstep Keys in Track View

  1. Select Bip01 and right-click, then choose TrackView selected.

  2. Make sure Animated Tracks Only are showing.

  3. Right-click on Bip01 and choose Expand Tracks.

  4. The Bip01 Footsteps track is displayed in Track View.

    Tip: If Bip01 Footsteps track is not displayed, turn on Footstep mode in the Motion panel and the track will appear.

  5. Scroll until you see the footstep track, (the blue and green blocks next to Bip 01 Footsteps).

    Footsteps in Track View

    Each blue block represents a left footstep and each green block represents a right footstep. The length of the blocks is the period of time the foot is in contact with the ground during the footstep. The spaces between the blue and green blocks represent periods in which the biped is not supported by the left or right foot. Make sure you can see some other biped tracks as well.

  6. Select footsteps 11 through 15 by drawing a box around them in Track View.

    Notice that footstep number 11 starts at frame 166.

  7. Click in the center of footstep 11 and drag it to the right until the number 166 (indicating the first frame of footstep 11) increments to number 180. Release the mouse button.

    Shift the keys to the right to create a gap.

    The keys in the other biped tracks adjust to the change in the footstep track.

    You have changed a walking step into a jumping step by creating an area in the footstep track where neither foot is supporting the biped.

  8. Close Track View and play the animation.

    The gap between footsteps creates a jump.

Crouching before the jump

The preparation for the jump, between footsteps 9 and 10, looks a little stiff because the biped is not crouching enough before jumping. Resetting a vertical key will fix this.

  1. On the Track Selection rollout, click Body Vertical.

  2. Scroll to frame 153, where there is a Body Vertical track key.

  3. Select and move the center of mass down approximately -5 units.

    Lower the vertical track.

  4. On the Keyframing rollout, click Set Key to set the vertical track key.

  5. Move the time slider to view the animation.

  6. Select Bip01 R Foot. Move the time slider to frame 167 and raise the foot so it's above the ground (approximately 4 units). Set a key to hold it there. Set additional keys on the foot if it swings through the ground.

  7. Play back the animation.

    The jump looks smoother. The result should be similar to cs3walk9.bip.


    Lesson 3: Creating Gymnastic Motion Flips with Ballistic Tension