Tutorial 3: Animating a Biped with Footsteps

Lesson 1: Creating an Expressive Walk

In this tutorial, you'll use Biped to animate a character walking, using a default motion that is created automatically.

This sophisticated yet simple approach results in a natural-looking motion that is quick to create. You'll refine the motion, changing the default walk into something more expressive.

Setup

  1. Reset 3D Studio MAX.

  2. Open cs3_tut03_start_walk.max.

    The files for this tutorial are in the cstudio\tutorials\tutorial_3 directory in your 3DS MAX path. If the files are not installed on your system, you can load them directly from the Tutorials directory of the character studio 3 CD.

    A biped is standing at the origin.

    Biped at center of grid

  3. Maximize the Perspective viewport by pressing W.

  4. Click any part of the biped.

    A white box outlines the body part you clicked, to show it's selected.

  5. Open the Motion panel.

    The Biped controls are displayed. Figure mode is active.

    Next you'll turn on Footstep mode. Figure mode turns off automatically.

Using Footstep Mode

  1. In the General rollout of the Motion panel, turn on Footstep mode.

    The Footstep mode button turns yellow and the Footstep Creation and Operations rollouts are displayed.

  2. In the Footstep Creation rollout, click Create Multiple Footsteps.

    The Create Multiple Footsteps: Walk dialog is displayed.

    You'll just change the number of footsteps, leaving the other defaults as they are.

  3. In the Create Multiple Footsteps: Walk dialog, change Number of Footsteps to 8 and click OK.

    Footprints are displayed in white in the viewport. These are inactive footsteps. They do not yet control any animation for the biped.

    Footsteps

  4. In the Footstep Operations rollout, click Create Keys for Inactive Footsteps.

    The Footsteps are activated. Animation keys are created for the biped.

  5. Play the animation.

    The biped walks.

    Biped walks.

  6. Turn off Footstep mode.

    The track bar displays keys for the length of the animation.

    Track bar displays keys.

    The biped walks, but without much character. In the next steps, you'll begin individualizing the motion by bending the biped's spine back and forth over the keyed animation frames.

Adding spine motions

  1. In the Front viewport, click one of the biped's spine objects.

  2. Open the Motion panel.

  3. On the General rollout, click Bend Links mode. Bend Links mode lets you bend all the spine elements when the first spine link is rotated.

    Note: This figure only has two spine elements. The effect is more pronounced on a biped with more spine objects.

  4. Turn on Animate and move the time slider to frame 24.

  5. Rotate the spine approximately -12 degrees about the Y axis to move the hips down towards the leg that is in motion.

    Rotate the spine.

  6. Click the Key Mode button to turn on Key mode.

    Key mode lets you use Previous and Next Key buttons to jump between keyframes for the selected object.

  7. Click Next Key to move to frame 40.

  8. Rotate the spine 12 degrees about the Y axis.

  9. Move to frame 54 and rotate the spine -10 degrees about the Y axis.

    Repeat this pattern until you have finished rotating the spine at the end of the animation. Do not make your adjustments too precise. Slight variations from frame to frame make the motion look more natural.

    When you are done, play the animation and notice the increased hip swings that result from bending the spine back and forth.

  10. Turn off Bend Links modes

  11. Turn off Animate.

  12. On the General rollout, click Save File and save the file as mywalk.bip.

    If you load the newly saved mywalk.bip file into a scene containing a skinned character, the character will swing its hips according to the instructions you saved in the file. You may need to adjust it, play the animation to determine if it is necessary.

    Animation applied to Dr. X

    If you made a mistake during the previous steps: use Load File on the General rollout to load the file cs3walk1.bip. Otherwise, just keep working with the file that's open.

    Next, you accentuate the biped's hip motion by rotating the pelvis.

Adding hip motions

  1. Turn on Animate, and move the time slider to frame 24.

  2. On the Front viewport, use Rotate to select the biped's pelvis.

  3. Rotate the pelvis -8 degrees about the Y axis, moving the left leg down.

  4. Make sure Key mode is still on, and then go to frame 40.

    Tip: When Key mode is on, you can use the time slider arrows to jump to the next key.

  5. Rotate the pelvis 8 degrees about the Y axis, moving the right leg down.

    Continue this pattern until you have finished rotating the pelvis to the end of the animation.

  6. Turn off Animate.

  7. Play the animation to see the increased hip motion.

    Added pelvis rotation

  8. Save your file as mywalk1.bip.

    At this point, you can either keep working with the current file or load cs3walk2.bip to compare it with what you have done.

Adding hand motions

Arm and hand motions are an integral part of an individual's movement when it walks. In the following sequence, you'll move the biped's hands at its wrists using Track View and then add irregular motion to each frame to make the movement more life-like.

The keys for the hands, forearms and upper arms are all stored in the Clavicle tracks. You'll use Track View in the next sequence.

  1. In the Front viewport select Bip01 R Clavicle.

    The right clavicle

  2. Right-click the selected object and choose Track View Selected.

  3. Expand the transform track.

  4. On the Motion panel, in Track Selection, click Symmetrical.

    This adds the left clavicle to the selection set.

  5. Expand the transform track for the left clavicle.

    If you can't see all the frames in the animation in the Track View Edit Window, click Zoom Horizontal Extents.

  6. Select all the left and right clavicle keys by drawing a selection region around them in the Track View Edit window.

    The selected keys turn white.

  7. Minimize Track View.

  8. On the Keyframing rollout, click Set Multiple Keys to display the Biped Multiple Keys dialog.

    Note: Use this dialog to apply a transformation equally to all keys. The change is relative to the original position and any differences between keys are maintained. It operates on existing keys and does not create new keys. Therefore, you do not have to be in Animate mode or use the biped Set Key buttons to use it.

  9. On the 3DS MAX main toolbar click Rotate, and select the biped's right hand.

  10. On the Motion panel, on the Track Selection rollout, click Symmetrical Tracks to add the left hand to the selection.

  11. In the Front viewport, rotate the hands 30 degrees about the Z axis to tilt them away from the body.

    Rotate hands away from body.

  12. On the Change Multiple Keys dialog, click Apply Increment to apply the rotation to all the hand keys.

  13. Close the Change Multiple Keys dialog and Track View.

  14. Play the animation.

    The constant angles of the hands give them a mechanical look. To rectify this you'll adjust each frame in which a hand key is set.

Adjusting the hand positions

You'll be repeating the procedures again here. There's plenty of repetition in animation work. This should reinforce your learning.

  1. Use Rotate to select one of the hands, and click Symmetrical Tracks (on the Track Selection rollout) to add the other hand to the selection.

  2. Turn on Animate, make sure Key mode is turned on, and lock the selection.

  3. Jump to the next key.

  4. Rotate the hands approximately 10 degrees about the Z axis.

  5. Jump to each key and rotate the hands slightly at each frame until you've adjusted the last frame.

    Note: You can also select the hands separately and adjust each one differently.

  6. At this point, you can either save your mywalk.bip file or go back and make further adjustments before going on.

    Tip: For longer animations, Use Change Multiple Keys to add irregularities. Select every other key or select a random series of keys instead of selecting them all.

  7. Play the Animation in the Perspective viewport.

Keeping the arms from passing through the body

The upper arms might pass through the biped chest (depending on how you rotated the pelvis). You can fix this with a few additional rotation keys.

  1. Turn on Animate, if it isn't already.

  2. Select and rotate the Bip01 L UpperArm away from the body (about the Y axis) at the frames where the arms pass through the body. (approximately frames 39, 68, and 99).

    Tip: You can enter the frame numbers in the Current Frame field in the Time Controls to move directly to the frame you need.

    Rotate the arm away from the body.

  3. Repeat step 1 for the right upper arm. Add rotations at frames 25, 55, 86, and 115.

Adding head motions

You can edit the biped's head motion to make the character's motion look natural.

  1. Turn on Animate, if it isn't already.

  2. Turn on Key mode, if it isn't already.

  3. Move the time slider to frame 0.

  4. In the Front viewport, select the biped's head using Rotate.

  5. Click Next Key twice to move to frame 40.

  6. Rotate the head -20 degrees about the X axis to turn the head to the biped's left, and -8 degrees about the Z axis to make the biped's head turn left and up.

  7. Continue to jump through the head's keys, setting rotations to animate the head.

    Natural head motion is smooth, so the orientations should change gradually from one key to the next.

    Rotation of head at frame 69

  8. Turn off Animate and Key Mode.

  9. Play the animation and notice how much the biped's side-to-side and up and down head movements add to the animation.

    You can now save your work as mywalk2.bip. You can check your file against cs3walk3.bip.

Next

 

 

 


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