Skin > Bind Skin > Smooth Bind

You can bind geometry to any transform node or hierarchy of nodes such as an empty group node or a locator. For example, you can now create a deformation effect by binding a polygonal mesh to locator nodes that are connected to the CVs of a spline curve.

With either Closest Joint or Closest Distance, you can limit the number of joints that influence nearby skin points by setting Max Influences. You can also limit the joints’ range of influence by specifying Dropoff Rate.

Skin > Bind Skin > Smooth Bind >

Bind to

Specifies whether to bind to an entire skeleton or only to selected joints.

Joint Hierarchy: Specifies that the selected deformable objects will be bound to the entire skeleton, from the root joint on down through the skeleton’s hierarchy, even if you have selected some joint other than the root joint. Binding the entire joint hierarchy is the usual way to bind a character’s skin.

Joint Hierarchy is the default Bind to selection.
Selected Joints: Specifies that the selected deformable objects will be bound to only the selected joints, not the entire skeleton.
Object Hierarchy: When this option is selected, the selected deformable geometry is bound to the entire hierarchy of the selected joint or non-joint transform node, from the top node down through the entire node hierarchy. If there are any joints in the node hierarchy, they are also included in the bind. With this Bind to option, you can bind entire pieces of geometry to nodes like groups or locators.

NoteWhen using the Object Hierarchy option, you can only select joints or objects that cannot be skinned (for example, group nodes or locators—not pieces of geometry) as the initial influences in the bind.

Bind Method

Specifies whether joints will influence nearby skin points based on the skeleton’s hierarchy, or only on joint proximity to skin points. Selections include Closest Joint or Closest Distance.

Closest In Hierarchy: Specifies that joint influence is based on the skeleton’s hierarchy. In character setup, you will usually want to use this binding method because it can prevent inappropriate joint influences. For example, this method can prevent a right thigh joint from influencing nearby skin points on the left thigh.

Closest In Hierarchy is the default Bind Method.
Closest Distance: Specifies that joint influence is based only on proximity to the skin points. When binding skin, Maya ignores the hierarchy of the skeleton. In character setup, you will usually want to avoid this binding method because it can cause inappropriate joint influences. For example, this method can cause a right thigh joint to influence nearby skin points on the left thigh.

Max Influences: Specifies the number of joints that can influence each skin point. Default is 5, which is a good choice for most characters. You can also limit the range of joint influence by specifying a Dropoff Rate.

After Bind

Select the option.

Maintain Max Influences: When on, your smooth skinned geometry cannot have, at any time, a number of influences greater than that specified by Max Influences.

For example, if Max Influences is set to 3, and you then paint or set weights for a fourth joint, one of the weights of the other three joints is set to 0 to maintain the total number of weighted influences specified by Max Influences.

This limits the redistribution of weights to a specific number of influences, and ensures that the primary joints are the ones that receive the weights.

NoteIf you turn on Maintain Max Influences in the Attribute Editor, your skin’s weights will not be modified until you reassign the skin weights by clicking the Update Weights button.

Dropoff Rate: Specifies how rapidly the influence of each joint on skin points will decrease with the distance from each joint (and the joint’s bone). The greater the Dropoff Rate, the more rapid the decrease in influence with distance. The lower the Dropoff Rate, the further the influence of each joint. When you bind skin, the Dropoff Rate applies to all the selected joints. Use the slider to specify values between 0.1 and 10. You can enter values up to 100, but values between 0.1 and 10 are ideal for most situations. Default is 4, which provides good deformation effects for most characters.

After binding skin, you can use the Paint Skin Weights Tool to edit the influence of joints in an intuitive manner. For more information, see Painting smooth skin point weights.
Remove Unused Influences: When on, weighted influences that would receive a zero weighting are prevented from being included in the bind. This option is useful when you want to reduce the number of calculations for your scene to increase your scene’s playback speed.

NoteThe Remove Unused Skin Influences option in the Optimize Scene Size Options window also lets you remove any zero weighted influences from your character’s skin bind.
For more information on the Optimize Scene Size window, see File > Optimize Scene Size.
Colorize Skeleton: When on, your bound skeletons and their skin’s vertices are colorized so that their vertices appear the same color as the joints and bones that influence them.

NoteYou can change the colors of individual joints and bones from the Display > Wireframe Color window.