INSIDE 3DS MAX® 7 [Electronic resources]

character studio

Happy dayscharacter studio (cs), formerly a separate program, is now included with and fully integrated into 3ds max 7. character studio works with 3ds max 7's standard bones, weighted controllers, keyframing tools, and skinning options. cs is covered in much more depth in a later chapter, but we will take a brief look at its new features here.

character studio offers a variety of tools for maintaining accuracy and troubleshooting character animation with a set of specially linked objects collectively called a Biped. This Biped is color-coded green on its right side and blue on its left to simplify the display of its rigging and animation features (Figure 4.19).

With Biped you can quickly create ready-made character rigs and make adjustments to With Biped you can quickly create ready-made character rigs and make adjustments to the creation parameters. Most of the parameters for using the Biped are within the Motion panel. Let's examine the Biped's animation modes.

Figure Mode

Figure mode (in the Structure rollout) helps you create the Biped's internal structureit's basically an automated rigging system. You can make the following assignments: Arms, Neck Links, Spine Links, Leg Links, Tail Links, Ponytail1 Links, Ponytail2 Links, Fingers, Finger Links, Toes, Toe Links, Props, Ankle Attach, Height, Triangle Pelvis, Forearm Twist, Forearm Links, and Body Type (Figure 4.20).

Use Figure mode to align, scale, and rotate parts of the Biped structure to fit your modeled characters. Biped also saves you time when creating a character rig by enabling copy-and-paste bones mirroring (Figure 4.21) using Copy and Paste Opposite to duplicate the posture or pose of a portion of the Biped. You can rig one side of the Biped and have Figure mode rig the other.

Proper alignment in Figure mode saves time you would otherwise spend making corrective adjustments to Skin modifier animation (Figure 4.22).

Footstep Mode

character studio offers a variety of useful procedural animation tools and aids. Footstep mode allows you animate the walking path of a Biped-rigged character throughout a scene. The method is fairly simple: Footstep mode can be activated from the Biped rollout from the Motion Panel and when any part of the Biped is selected. After activating the Create Footsteps button from the Footstep Creation rollout, you click in the Perspective viewport to place positional markers called Footsteps that indicate where and when the Biped will walk, run, or jump. Left and right Footstep sub-objects set the path for the Biped's corresponding feet. These Footsteps keep the Biped's feet locked to the ground on their designated frames.

When Footstep mode is active, you can only select, delete, position, rotate, and change the duration of the Biped's footsteps. Editing the timing of the Footsteps is done from the Curve Editor in the Dope Sheet mode (Figure 4.23). The Biped's body instantly reacts to changes in the curve.

Leg functions include Plant, Move, Touch, and Lift. When a leg is planted, it sticks to the ground. When a leg moves, it travels from one Footstep to another. If both Biped legs are moving at the same time, then the Biped is jumping, running, or performing some other motion with both feet in the air.

Footsteps cause other parts of the Biped to automatically generate keys. For example, if the Biped has a tail, it will automatically sway back and forth in sync with each step. You can assign a "freeform area" between Footsteps to accommodate Biped animation that does not involve a relationship between foot and ground, such as swimming or reclining in a chair.

Once you are finished animating a Biped, you can save the animation for use in other areas of character studio such as Motion Flow mode, Mixer mode, and the Motion Mixer. Or you can apply the animation to a Crowd of other Bipeds.

Note

Motion Flow Mode

Motion Flow mode is activated from within the Biped rollout. From Motion Flow mode, you can take saved Biped animations, including motion-capture (mocap) files, and create a transition between them. For example, you can load an animation of a Biped performing a ballet and transition this into another animation of the Biped slipping on a banana peel, producing a comical animation of the Biped dancing a few steps, then slipping and falling down (Figure 4.24).

This sort of procedural animation assemblage can be very useful, but be aware that the animation clips may not work perfectly together. character studio does not necessarily know how cartoony you want that ballerina's fall to be, or just how hard she should hit the ground. Some good old manual keyframing may still be necessary.

Mixer Mode and Motion Mixer

Mixer mode is activated from the Biped rollout and the Motion Mixer is opened from the Biped Apps rollout. Mixer mode and the Motion Mixer work together. When Mixer mode is active, the Biped responds in the viewports to changes made to it in the Motion Mixer, and the Save File button is available. The Motion Mixer is used to mix together different Biped animations and filter different areas of the Biped. For example, you can take the upper-body animation of one Biped and the lower-body animation of another and mix them into one animation (Figure 4.25). The effect can be a timesaver when you need to quickly move a lot of characters with a few motions. A curve editor controls how much of the upper body will animate and when.

In the Motion Mixer, you can also graphically edit and warp the time range of the animation files. For example, you can make the Biped move in slow motion during designated frames, then speed it up to normal again. The completed mix can be consolidated into a single animation file for the final animation.

Biped Animation Mode

Once the Biped has been created, Footsteps added, and Motions mixed, you will probably want to tweak the animation. You may have positioned the Footsteps in the correct locations and times, but the Biped's head and pelvis might need to be animated differently. For this you need to exit all previously mentioned modes and enter Biped Animation mode.

Once in Biped Animation mode, you can select and animate the Biped's individual parts, such as the arms and head, using standard keyframing and kinematics. You can also change between forward kinematics (FK) and inverse kinematics (IK) using the IK blend slider (Key Info > IK Blend).

With FK, you animate down the bone hierarchy chain from parent to child. In FK, moving the upper arm moves the hand. Since the Biped hand is a child of the forearm, it will follow. IK works in the opposite way, up the bone chainyou use the child to move the parent, the hand to move the upper arm. For example, if you temporarily constrain the Biped hand to an object, when that object moves, the Biped hand and entire arm will follow, to the limits of the rig's extensibility. (Note that under IK, rotation of the upper arm does not have a blended effect based on a Blend value for the keyframe.)

Many animators prefer to animate parts of the body using mainly one system or the other, but you really need both systems to animate characters effectively. Switching back and forth between FK and IK allows you to animate with the greatest degree of control, as well as to take advantage of special capabilities such as having the hands and feet controlled by moving objects in the scene. IK/FK blending makes it easier to throw and catch objects or pass an object from one hand to the other, simple actions that can be surprisingly hard to animate with only one form of kinematics.

The technique is not difficult. To pass an object such as a football from hand to hand, you first create a key with the Set Key button, pick the football as the object, and set IK Blend (in the Key Info modifier) to 1.0. This allows the animated football to be passed from the right Biped hand to the left (Figure 4.26).

Another trick new to 3ds max 7 is the ability to set when the Biped's head will look at and follow the animation of other objects in a scene. A Biped head can track and look at one object passing, then turn to track another object traveling in a different direction. You only need to animate the objects and the Biped's head will follow.

The designated LookAt object can be animated either before or after the Target Blend values are entered.

Note

Following is a quick mention of other new character studio Biped features. The character studio Help Reference in the 3ds max 7 User Reference is the place to go to learn more about these Biped abilities.

• The location of the foot pivot point can change from the back to the front of the foot at different frames of the animation. When you animate the location of the foot's pivot, the weight of the walking Biped will appear to transfer more realistically through the feet.

• Biped has a built-in system to animate rotations and do its best to avoid unwanted limb flipping (a common problem with character rigs caused mainly by the limitations of current IK solvers and the use of Euler rather than quaternion rotational data). This allows you to animate the rotation of Biped joints without having to add keys just to fix rig problems.

• In many cases, you need to play with several types of animation ideas until you know what you want. For this, Biped offers you the same flexibility that a photo-editing program offers with layers. By adding layers, you can turn parts of the animation on and off and flatten the animation to a single track when satisfied.

• A Visual Clipboard is available to manage animation tracks and character poses. You can easily find and substitute pose data between characters.

• A set of tools within a Biped application called the Workbench is available to clean up and correct rig-based animation problems, such as unwanted jerking. You can use Workbench tools to smooth the keyframes for a more natural motion.

• Import, manage, and edit mocap data for use with the Biped. character studio has tools to aid you in tweaking mocap files from a real performer that do not calibrate with your 3ds max 7 scene.

• Use layers to test out variations in your animation, and turn these variations off and on. For example, you can put Biped spine animation on its own layer. When that layer is applied, the character will sway differently when it walks. Changes to this layer can then be removed or turned off if you aren't satisfied, returning the animation to its previous motion. Layers can be stacked to see the effects of multiple motions, and then collapsed into a single animation.

• Use Crowds to combine many different saved Biped animations into a flock of characters with various behaviors. Biped characters can be set to act as if they were attracted to or repelled by other objects or characters in the scene.