This lesson provides an introduction to using freeform animation techniques with Biped.

In this lesson, you will animate a biped swimming in place. You’ll use freeform animation methods to produce the kicking legs and arm strokes.

In order to create this motion, you’ll use a combination of rotations and moves. You'll also make use of Copy and Paste Posture Opposite to animate one arm and copy its tracks to the other.

Set up the lesson:

1. Reset 3ds Max.
2. On the Create panel, click (Systems).

Create a biped and load a FIG file:

1. Click to turn on (Biped), and then create a biped in the Front viewport.
2. Go to the Motion panel.
3. Turn on (Figure Mode), then click (Load File).

   3ds Max displays the Open dialog.

4. Open the file tut_swimmer.fig. This file is in the folder \sceneassets\animations\.

   The biped takes on new structural elements saved in the FIG file. This simplified figure has one large toe on each foot and one large finger on each hand, and its spine contains two segments instead of four.

   

   The biped with FIG file applied.

5. Turn off (Figure Mode).
   NoteYou cannot animate in Figure mode.
6. Select all the biped objects, and then click (Zoom Extents All).
7. Save the scene as MySwimmer01.max.

Start a freeform animation:

You start a freeform animation by activating automatic key recording and transforming any part of the biped.

1. Right-click the Left viewport.

   This activates the Left viewport without affecting the selection in the scene.

2. Press Alt+W to maximize the viewport for a closer view of the biped.

   The biped should be in wireframe. Change the shading display of the Left viewport if it is not wireframe.

3. Turn on (Auto Key).

   The button turns red, and the active viewport is outlined in red.

4. On the Motion panel Track Selection rollout, click (Body Rotation).
   NoteActivating any of the Body ... buttons on the Track Selection rollout automatically selects the center of mass (COM) object.

   

   Rotation transform gizmo

   The rotation transform gizmo lets you easily rotate an object about a chosen axis. As you move your cursor over the gizmo in the viewport, the axis circles turn yellow, indicating the axis around which the rotation will occur:

   • The red circle, displayed as a vertical line in this viewport, affects the X axis.
   • The green circle affects the Y axis.
   • The blue circle, displayed as a horizontal line in this viewport, affects the Z axis.
   • The light gray circle, displayed around the green circle, allows free rotation around all three axes.
5. Move your cursor over the green circle.

   The cursor turns yellow, meaning that any rotation is locked to that axis.

6. Rotate the center of mass approximately 90 degrees about the Y axis. Watch the coordinate readout near the gizmo to see how far you're rotating the biped. Rotate until the biped is lying prone.
   TipIf you like, you can press A to turn on Angle Snap, which lets you easily rotate to 90 degrees.

   

   An animation key appears at the far left of the track bar, at frame 0.

   You can select all three COM tracks under Track Selection to create keyframes simultaneously. Try this:

7. On the Track Selection Rollout, click (Lock COM Keying), and then click (Body Rotation).
8. On the Track Selection rollout click to turn on both (Body Horizontal) and (Body Vertical).

   All the multiple tracks for the COM are now active.

   

9. Expand the Key Info rollout and click (Set Key).

   This sets keys for all the COM tracks at frame 0. The trackbar key shows a multi-color display, indicating that both position and rotation keys have been created.

10. Click Lock COM Keying again to unlock the COM tracks.
    TipIt’s a good idea to set a key at the start of your animation for the three COM tracks.

Pose one leg:

Now that the biped is prone, you're ready to animate the swimming motion. First, you’ll position the legs. You’ll work on the right leg first, setting up its position at frame 0.

1. Press Alt+W so you can see all four viewports again.
2. Select Bip01 R Thigh by clicking the lines of the thigh in the Left viewport.
   TipAs you hold your cursor over an object in the viewport, the object’s name is displayed in a tooltip. You can also select an object by pressing H to choose objects from the selection list.

   

   The right thigh is selected.

3. Rotate Bip01 R Thigh approximately −30 degrees about the Z-axis.

   The right leg is rotated, but the right foot is pointing straight down.

   

4. Press Page Down twice to select the right foot.
   TipThe Page Up and Page Down keys let you quickly navigate through the objects that make up a biped.
5. Rotate Bip01 R Foot about –50 degrees around the Z-axis.

   The foot looks more natural in this position.

   

   So far you’ve used only forward kinematics to animate the biped. Next you’ll use inverse kinematics by moving the foot to move the entire leg.

6. Right-click the same foot and choose Move from the quad menu.
   TipYou can choose the transform tools either from the main toolbar or by right-clicking to open the quad menu.

   The Transform gizmo switches to an axis tripod showing two of three arrows in this viewport. They are displayed at right angles with the Z axis pointing up and the Y axis pointing left.

   

   Ready to move the foot.

7. In the Left viewport, move the cursor over the Y axis of the gizmo until it turns yellow, then move the foot a little to the right.

   The knee bends to accommodate the new position of the foot.

   

   The knee bends.

   In this move, you’ve just used inverse kinematics. The foot, calf, and thigh are linked together in a hierarchical chain. By moving the end of the chain, the foot, you rotated the lower and upper leg objects.

8. Save the scene as MySwimmer02.max.

Animate the leg:

Everything you’ve done so far has been at frame 0. Now you’ll move forward in time and animate the pose at frame 10.

1. Drag the time slider to frame 10.
2. Move the foot downward on the Z axis until the knee straightens out.

   

3. Press Page Up twice to select Bip01 R Thigh.
4. Right-click and choose Rotate from the quad menu, then rotate the Bip01 R Thigh approximately −10 degrees about the Z axis.

   

   Rotating the thigh.

5. Scrub the time slider back and forth between frame 0 and frame 10.

   The leg moves up and down.

Use copy and paste:

Now you’ll use some specialized Biped tools to pose and animate the opposite leg.

1. Return the time slider to frame 10.
2. Double-click Bip01 R Thigh.

   The entire leg is selected from the thigh down to the toes.

   

3. On the Motion panel, expand the Copy/Paste rollout.

   The Copy/Paste functionality includes the creation of collections. You must create a collection before you can start creating postures.

4. On the Copy/Paste rollout, click (Create Collection). This creates a collection named Col01. Rename it to Swim – Crawl.
5. Make sure that the Posture button is active.

   

6. Also make sure that Capture Snapshot From Viewport is chosen. This button is just above the Paste Options group.

   

   Choosing Capture Snapshot From Viewport forces the thumbnail of the pose to be taken from the active viewport. This particular posture, for example, is better seen from the Left viewport rather than the Front.

7. Click (Copy Posture).

   

   The posture of the right leg is copied into a buffer. Change the name of the Copied Posture to RLeg – downkick.

8. Drag the time slider back to frame 0. Click (Paste Posture Opposite).

   The left leg rotates downward. The right leg hierarchy is still selected.

   

9. At frame 0, click (Copy Posture) again.
10. Drag the time slider to frame 10.
11. Click (Paste Posture Opposite) again.

    Now the left leg is raised, and the right leg is down.

    

12. Scrub the time slider back and forth between frames 0 and 10 and watch the legs kick.

    Now you‘ll repeat this process to make the legs kick several times.

13. Save the scene as MySwimmer03.max.

Use Paste Posture to create multiple kicks:

You can use the Copy Posture tools to quickly duplicate all the leg keys from one frame to another to create repeated kicking motions.

1. Make sure that (Auto Key) is still on and drag the time slider to frame 0.
2. On the Track Selection rollout, click (Symmetrical).

   Now both legs are selected.

   

3. At frame 0, click (Copy Posture). Name the copied posture R up L down.

   

   Both legs are added to the collection.

4. Drag the time slider to frame 20.
   TipYou can type in the frame number in the Current Frame time control.

   

5. At frame 20, click (Paste Posture).
6. Go to frame 30 and click (Paste Posture Opposite).

   From this point forward, you can click either Paste or Paste Opposite as you create a kicking cycle. For a smooth kick cycle, simply alternate the posture every 10 frames up to frame 80. The track bar displays a total of nine keys for the animation of the legs.

7. In the Copy Collections group click the Save Collection button to save your collection. Name the collection Swim – Crawl. The CPY extension is automatically added to the name.
8. Save the scene as MySwimmer04.max.

Animating a kicking leg was fairly easy, requiring only two poses: one with the leg up, and one with the leg down. Animating the arms is more complex. To animate the stroke of an arm, you’ll need five poses:

• The arm outstretched
• The arm down
• The arm back
• The arm drawn up out of the water near the ear
• The arm entering the water

When one arm is animated correctly, you’ll use Copy Track and Paste Opposite Track to animate the second arm. You’ll adjust the timing of the second arm by sliding the keys in the track bar.

Animate one arm:

1. Make sure that (Auto Key) is still on, and drag the time slider to frame 0.
2. Press H. In the Select From Scene dialog, select Bip01 L UpperArm.
3. In the Left viewport, rotate Bip01 L UpperArm approximately −160 degrees about the Z axis, until it is extended in front of the biped.

   

4. Right-click the Top viewport and press Page Up to select Bip01 L Clavicle and rotate it −20 degrees about the Y axis.

   This should prevent the arm from passing through the head.

   

5. In the same viewport, press Page Down three times to select Bip01 L Hand. Rotate it approximately −90 degrees about the X axis so the palm is facing down.

   

   This completes the first arm pose, so it's a good time to save your data.

6. Double-click Bip01 LClavicle to select the entire left arm hierarchy.
7. Activate the Perspective viewport so that the snapshot will be easier to identify, and then click Copy Posture. Name the pose LArm extended.

   

   Thumbnail snapshot from perspective viewport.

8. Drag the time slider to frame 10.
9. On the main toolbar, click (Select And Move), and then change the Reference Coordinate System to World, if it isn’t already set to World.

   

   This will facilitate working with the Transform gizmo in different viewports.

10. Right-click in the Left viewport. Move Bip01 L Hand downward on the Y and Z axes until it points straight down. This completes the second arm pose.
    TipIf you grab the Move gizmo by the corner where the two axes meet, you can move selected objects on both axes at once; that is, on the YZ plane.

    

11. Double-click Bip01 LUpperArm to select the arm hierarchy, then click (Copy Posture). Name the pose LArm down.
12. Drag the time slider to frame 20.
13. Move Bip01 L Hand along the Y axis toward the legs.

    

14. Activate the Front viewport and press Page Up three times to select Bip01 L Clavicle. Rotate this part about 24 degrees around the Z axis.

    This completes the third arm pose. Save it by double-clicking Bip01 L UpperArm in the Top viewport to select the hierarchy, then click Copy Posture. Name the pose LArm back. If you activate the Perspective viewport before you copy the posture, you can adjust the viewport so the pose is clearly visible in the thumbnail.

    

15. Drag the time slider to frame 30.
16. Activate the Top viewport.
17. Move Bip01 L Hand in the XY plane until the hand is level with the shoulder.

    

18. In the Left viewport, move Bip01 L Hand on the Z axis so it is near the ear.

    

19. Finally, rotate Bip01 L Hand about the X axis so the palm is flat.

    This completes the fourth arm pose. Save it to the collection by double-clicking the upper arm to select the entire hierarchy, then click (Copy Posture). Name the pose LArm up.

    

    

20. To create the fifth pose, go to frame 37.
21. In the Left Viewport, move the Bip01L Hand object on the Y axis so it is in front of the head, and is level with the shoulders. Double-click the Bip01 L Upperarm to select the entire arm hierarchy, activate the Perspective viewport, and then click (Copy Posture). Name the pose LArm stroke.
    NoteThe fifth pose is used to ensure that the rotation of the arm is correct going from the out-of-water pose to the extended pose.
22. Save the scene as MySwimmer05.max.

Applying a twist pose:

You can use twist poses to correct upper arm rotations. Twist poses are primarily used to correct arm twisting, but in this case we’ll use it to simply position the arm efficiently.

1. Turn off (Auto Key) if it is on.
2. Select Bip01 L Upperarm.
3. Drag the time slider to frame 33.
4. Expand the Twist Poses rollout.
5. In the Twist Poses drop-down list, choose each pose and observe the change to the arm in the viewport.

   Consider these default poses as additional copied postures that you can use to “straighten out” problems by defaulting to fixed rotations.

   

   Twist Poses

6. When pose 5 is selected, the arm will be rotated and positioned correctly. Expand the Key Info rollout and click (Set Key) to keyframe the twist pose.

   

   Default Twist pose 5.

   TipTwist poses are designed to help you fix twisting that occurs in the mesh attached to the biped. If you go to Figure Mode, you can enable Twist Links by turning on the Twists check box, then set the number of twist links you would like for the upper arm, forearm, thigh, calf, or “horse-link” (the extra link in the Leg if Leg Links are set to 4). Unfreeze and unhide all and you will be able to see the twist bones that have been added using this method. Once the Twist Links functionality is enabled you can play with the Twist and Bias settings.

Copy the Arm pose:

To complete the arm cycle, in the next few steps you’ll copy the arm pose to frame 40.

1. Turn on (Auto Key).
2. In the Top viewport, double-click Bip01 L Clavicle to select the entire left arm.

   

3. At frame 33, click (Copy Posture).
4. Advance the time slider to frame 40, and click (Paste Posture).

   If you see any unusual rotations or out-of-place movements, you can set additional keys to refine the animation.

5. Drag the time slider and watch the animation.

Repeat the animation:

If the animation is going to be 80 frames in length, you’ll need to repeat the arm movement.

1. Double-click Bip01 L Clavicle, to select the entire left arm, if it's not already selected.
2. In the track bar, drag a selection window around the keys for frames 10 through 40.
3. Hold down the Shift key and copy these keys by dragging them to the right. When the first key is over frame 50, release the mouse button.
4. Play the animation. The biped should perform two complete strokes with its left arm.
5. Save your scene as MySwimmer07.max.

Add rotation to the spine:

Next you’ll add some rotations for the spine to make the animation more convincing. This spine of this biped figure (tut_swimmer.fig) has only two segments. You’ll rotate the large section representing the upper torso.

1. Make sure that (Auto Key) is still on.
2. Select Bip01 Spine1.
   NoteThe first spine object is Bip01 Spine. The large second spine object is Bip01 Spine1.
3. Right-click the Front viewport.
4. Drag the time slider to frame 0, and on the Key Info rollout, click (Set Key).

   This sets a start key for the rotation.

5. Drag the time slider to frame 10 and rotate Bip01 Spine1 approximately −15 degrees about the X axis.

   This makes the body appear to follow the movement of the arm.

   

   Spine rotation

6. On the track bar, click the key at frame 0 to select it, then hold down the Shift key and drag a copy to frame 30. Watch the status area to know when you are at frame 30.

   

   The spine now rotates once in the 40-frame cycle.

7. Select Bip01 Pelvis.
8. Drag the time slider to frame 0, and on the Key Info rollout, click (Set Key).

   This sets a start key for the rotation.

9. Drag the time slider to frame 10, and rotate the pelvis a few degrees in X so it follows the movement of the left leg.

   

   Rotate the pelvis.

10. Copy these two keys to frames 20 and 30.
    TipFor the pelvis, you can also add a few degrees of rotation around the Y axis, if you like.

    Next, you’ll copy the pelvis and spine rotation keys to repeat the motion.

11. Make sure that the pelvis is still selected, then hold down the Ctrl key and click the Bip01 Spine01 object (the large torso spine object).
12. In the track bar, drag a selection rectangle around the four visible keys.
13. Hold down the Shift key and drag the keys so the leftmost key is copied to frame 40. Scrub the time slider back and forth to see the animation.

14. Copy the key from frame 0 to frame 80 to complete the set of keys.

    

    The final set of Bip01 Spine1 keys.

Animate the head:

The biped can breathe as it swims, if you animate the head rotation appropriately.

1. Make sure that (Auto Key) is still on.
2. In the Left viewport, select the biped's head, Bip01 Head.
3. Drag the time slider to frame 0, and rotate the head about 70 degrees around the X axis, so the biped’s left ear is pointing down.

   

   Rotate the head for breathing motion.

   TipWatch the Perspective viewport while rotating in the Left viewport.
4. At frame 20, rotate the head back down.

   

5. Hold down the Shift key and drag to copy the key at frame 0 to frame 40. Watch the status area to know when you are at frame 40.
6. Scrub the time slider to observe the head rotation.

   Actually, it would look better if the head were turned up at frame 30.

7. Slide the key you made at frame 20 along the track bar to frame 30. Do not hold down the Shift key for this step.

   The biped lifts and lowers its head once in the 40-frame cycle.

   TipYou can drag the time slider to frame 30, then slide the key on top of it.
8. To explore another way to copy keys, right-click the time slider.

   The Create Key dialog is displayed. This lets you create keys by choosing a source and a destination.

   

   TipYou don’t have to turn on Auto Key to set keys this way.
9. Set Source Time to 30 and Destination Time to 70, and then click OK.
10. Right-click the time slider again.
11. Set Source Time to 0 and Destination Time to 80, and then click OK.

This completes the head motion, but the right arm motions still need work. That comes next.

Animate the other arm with Copy Tracks:

Copy Tracks lets you copy and paste the animation tracks of selected objects to other objects, or to opposite body parts.

1. Make sure that (Auto Key) is still on.
2. In the Top viewport, double-click Bip01 L Clavicle to select the entire left arm.
3. Activate the Perspective Viewport.
4. On the Copy/Paste rollout, turn on (Track).
5. Click (Copy Track).

   The track is copied to the buffer. Name the track LArm – Crawl.

   

6. Click (Paste Track Opposite).

   

7. Play the animation.

   The biped is swimming the butterfly stroke. The two arms move together.

   Next you'll change the timing so the arms alternate.

8. In the Top viewport, double-click the Bip01 R Clavicle.

   The entire right arm is selected in the viewport.

9. Drag a box around all the keys in the track bar to select them. Slide all the keys 20 frames to the right.

   

   The biped swimming a freestyle stroke.

10. Play the animation.

    Now the beginning and end are not quite right. The easiest way to correct this is to copy and paste poses.

Fix the beginning and end:

1. Make sure that (Auto Key) is still on.
2. In the Top viewport, double-click the Bip01 R Clavicle to select the entire right arm, if it’s not already selected.
3. On the Copy/Paste rollout, click (Posture).
4. Drag the time slider to frame 50, and click (Copy Posture).
5. Drag the time slider back to frame 10, and click (Paste Posture).
6. At frame 40, click (Copy Posture), then at frame 0, click (Paste Posture).

   Now the arms alternate.

   

   To correct the other end of the animation, you can crop the animation to 80 frames.

7. In the time controls, click (Time Configuration).

   3ds Max opens the Time Configuration dialog.

   

8. In the Animation group, change the End Time to 80. Click OK.
   WarningDo not click Re-scale Time.
9. Play the animation.

Save your work:

1. On the Biped rollout, click (Save File) and save the motion as MySwimmer.bip.
2. Also save your final scene as MySwimmer08.max.

Perfecting the animation:

• If you like, you can improve the animation by adding some rotation keys to the pelvis and spine and by adding secondary motion to the feet and hands. Stagger the rotations of the extremities a few frames following the movement of the hands and feet.

To see a finished version of the swimmer, you can go to \scenes\character_animation\freeform_animation and open swim.max.