Understanding character studio Workflow

Create Skin Geometry

Create a basic skin shape for your character using any 3ds Max modeling tools and surface types. Be sure to place your character skin in a neutral pose with arms outstretched and legs spaced slightly apart. You might also want to add sufficient detail to your skin mesh or control points around joints to facilitate deformation during movement.

Create a Biped Skeleton

Biped automates the creation of bipedal character skeletons. It also lets you introduce significant changes to the skeleton structure and sizing at any point during your animation without adversely affecting character motion. As a result, you can animate your character without knowing if it is short or tall, skinny, or fat. It also means that if the director changes the character proportions, the animation still works.

For more detail on posing a biped skeleton, see Biped.

Attach the Skin

• Position the biped character within its modeled skin. Use Figure mode to scale bone lengths and to orient the skeleton correctly within the skin volume. Scale bone thickness as desired to achieve a good initial fit. Then save a figure file, so it’s easy to return to this pose.
• Use Physique to attach the skin geometry automatically to the biped or a 3ds Max bones hierarchy. The attachment is typically made to the root node in the hierarchy: the pelvis object on the biped or the root node on a bones hierarchy, not the center of mass. The attached skin is deformed as the biped or bones hierarchy moves.
• The links in the bones hierarchy are used to create a system of 3D envelopes that enclose nearby vertices. Envelopes typically overlap at the parent and child ends of links. Vertices within overlapping envelopes are blended to create smooth skin deformation over joints as the character moves.

Adjust Skin Behavior

Adjust Physique parameters and introduce skin behavior effects to achieve the desired characterization.

• Change default envelope shapes by adding cross sections and control points to isolate a more specific volume of vertices for each bone. Use exclusion lists or per-vertex weighting to apply fine-tuning control over individual vertices.
• Introduce bulge angles to change muscle shape based on the angle of a particular joint. Create tendons to simulate the motion of tendons under the skin, based on link movements.
• Adjust link parameters to change skin twisting, sliding, and creasing as the biped moves. Sliding allows the skin to compress at the biceps and forearm as the elbow is bent. Twisting controls the amount of skin twisting across a joint intersection.
• Create extra links using 3ds Max bones and dummy objects for added control. You can add links to the abdominal area to control compression, for example, or to create a link to animate the chest rising and falling as the character breathes. If a character has extra appendages, you can add 3ds Max bones to animate them. One common usage is to add a bone to animate the jaw.

Animate the Biped Skeleton

Once you’ve attached the skin to a biped structure, you can animate the biped freely and see the skin behavior update automatically, based on the current pose.

You can also choose to develop Biped animations in a separate scene entirely, and apply them to your final skinned character when you are satisfied with your final motion.

A Biped character is essentially an integrated hierarchy of bones that you can position freely using keyframes, IK goals, and footsteps. You can position a biped character using all the rotation and transformation tools found in 3ds Max.

Many of the 3ds Max coordinate systems can be used to position the biped. Local coordinates are useful to move a limb along its axis (the local X axis is always the axis along the biped limb); world coordinates are handy when there is any confusion regarding which way is up. You can use world coordinates as a home base. In 3ds Max, the world Z axis is always up.

Use Freeform Techniques

Biped provides a variety of methods for creating character motion easily. You can use a purely traditional approach by manually creating keyframes in freeform mode for different poses, letting the computer interpolate between joint positions and IK goals.

Use a Footstep-Driven Technique

You can also choose a partially assisted approach by using footsteps and Biped dynamics to help you create a default walk, run, or jump cycle. You can then adjust the biped keyframes and footsteps individually.

When using footsteps, biped dynamics helps you by simulating gravity and balance.

• Gravity can help in a jumping motion to accelerate a character during the falling period and to bend the legs naturally on landing.
• Balance enables retaining the character balance by adjusting its position when the spine is rotated and keyframed.
• Dynamics can be turned off on a per-key basis or for the entire animation. The animator can override center of mass keyframes created using Dynamics calculation at any time. Simply set the dynamic properties of these keys or choose Spline Dynamics for keys generated by newly created footsteps.

Convert Between Animation Types

Once you are satisfied with a particular footstep animation and its corresponding dynamic behavior, you can convert it to a freeform animation consisting of a simple combination of keyframes and IK goals. This intelligent conversion gives you control of animation behavior at every frame, for every joint of the character.

Use Layers to Apply Global Changes

Animation layers offer you a powerful tool for introducing global changes to an existing character animation. For example, you can convert an upright running motion into a crouched run by adding a layer on top of an existing run motion. The layer would contain a single keyframe with the biped's spine rotated forward. You can stack up layered changes, allowing you to refine your motion composition and eventually collapse your layers into a standard non-layered keyframe animation.

Use In Place Mode to Control the View

In Place Mode is a tool that lets you keep your biped in view during animation playback. It offers a convenient way of adjusting and adding keyframes to a character without constantly changing your view to follow the character motion.

Import Motion-Capture Files

You can import motion-capture files in BVH and CSM formats, edit them, and save them as BIP files. You can import these files with or without footsteps and dynamics and combine them in Motion Flow mode with other animations.

You can use the supplied motion-capture samples as is or adjust them to suit your needs using the collection of animation tools in Biped. The ability to import motion-capture marker files directly into character studio using the CSM file eliminates much of the cost of post-processing optical motion capture data. You can import motion-capture files with an additional prop bone, to define the motion of an object such as a sword or club.

You can also import HTR/HTR2 motion-capture files, as well as TRC files.

Motion-capture files can be imported with key reduction, making for more manageable tracks for subsequent editing.

Use Track View for Keyframe Editing

Track View allows you to edit keys and footsteps relative to the animation time line.

With Track View in Dope Sheet mode you can move footsteps in time. If you need a character to jump higher between footsteps, move the landing footsteps further away in time. Dynamics automatically compensate by making the character jump higher to keep it airborne longer.

You can also use Dope Sheet to specify a freeform period in a footstep animation. This allows you to take advantage of footsteps and dynamics for part of an animation, then switch to manual keyframing during the freeform period. This approach can be useful in animations where there is a mix of animation where the feet are on the ground and then off. Examples of this type of animation include running and diving, or walking and then sitting down.

Keyframe-adjustment tools allow the following:

• Find the next or previous key for the selected biped body part.
• Use the Time spinner to slide a key back and forth in time.
• Change Tension, Continuity, and Bias for a key.
• Display trajectories.

You can place arms and legs of a character into the coordinate space of another object or the world to simulate interaction with fixed or moving objects. In Freeform mode, for example, putting the legs into world space prevents them from sliding or moving when keyframing the center of mass of the character. Putting a hand in the coordinate space of a ball allows the hand to move wherever the ball moves.

character studio can take advantage of many 3ds Max tools. For example, you can use the Select And Link tool to attach objects to a biped.

If you want a character to pick up and carry an object and then put it down, you can use the Link controller to animate the duration of the attachment. 3ds Max bones can be used to animate character subassemblies, like pistons, and to create extra links for Physique.

Use the Motion Mixer to Mix Animations

You can use the Motion mixer to combine motions on a biped. For example, you could combine a walking motion with a cheering motion, and cause the biped to walk while cheering.

Use Motion Flow to Combine Animations

After you have created and modified various animation sequences, and stored them in biped motion files (BIP format), you can use Motion Flow mode to combine various motion files into longer animations that can be quickly previewed and edited. Motion Flow mode automatically places the animations end-to-end, allowing you to mix and match both freeform and footstep-driven motion files. Transitions between successive motions are automatically created for you, to provide a first-pass blending between overlapping frames of animation.

The Motion Flow transitions use velocity interpolation to create seamless transitions between clips. You can use the Transition Editor to modify a variety of blending parameters, including transition start frame, length, and angle between clips.

Refining Your Character

Great character animation is the result of many refinements that tune the overall personality of your character. You will find the need to refine progressively both the skinning behavior and the animation timing of your character. Biped and Physique make this iteration process straightforward by using the 3ds Max modifier stack and undo methods.

In addition, the ability of Biped to map motions between characters makes it easy to interchange great animations with existing characters, and tune their behaviors to achieve true integration of motion with character motivation and personality.

Use Crowds to Animate Groups of Characters

Once you've created animation sequences for characters or other models (such as a bird flapping its wings), you can replicate the models or characters and apply the motions to these groups using the Crowd Animation system. You can also combine them with a wide range of supplied behaviors to create lifelike activities in crowds, such as people streaming through a doorway, street traffic, or birds and fish flocking and avoiding obstacles. You can use Motion Flow mode to create motion clip networks. These allow characters to perform animation sequences appropriate to their current movement and transition smoothly between sequences. And you can use cognitive controllers in Crowd to transition between behaviors based on a variety of criteria. For more on crowd behaviors, see Creating a Crowd System.