Quick Guide

When properly installed the weightDriver plug-in should appear in the plug-in manager.

The weightDriver node can either be created manually or managed through the accompanying editor. Manual creation is used in case of utilizing the vector angle mode. The editor handles the pose related data when in RBF mode.

To start using the node use one of the following MEL commands:

// to create the node manually
createNode weightDriver

// automatically load the plug-in and open the Weight Driver Editor
weightDriverEditRBF

The weightDriver node can also be used in RBF mode through the RBF manager of mGear

Usage Vector Angle

In order to make the node work correctly you need to establish two connections.

The first tells the node the reference point for the vector calculation and is usually the transform node of the weightDriver shape node. The second connection comes from the node which serves as the target point for the vector, such as a locator, joint or other node.

• connect the weightDriver transform node worldMatrix to the weightDriverShape readerMatrix (depending on the editor you use you might have to display hidden attributes in oder to see the reader and driver inputs)
• create a locator and connect the locator transform node worldMatrix attribute to the weightDriverShape driverMatrix
• with both connections established the weightDriver node now displays the driver name and weight, which is the outWeight attribute you can now connect to any attribute you want to drive, for example a blend shape channel.

Usage - RBF

In most cases using the designated editor to create or edit a RBF setup is sufficient and the preferred way. However, in some cases it might be necessary to manually setup the weightDriver in RBF mode. In general, the following should be considered:

Rest Poses

Rest poses, if needed, should come first in the post list.

The reason for this is that Maya stores sparse arrays for it’s attributes, which means that if an array attribute contains a zero, it won’t get stored in the file. Rest poses often have many zeros and thus aren’t stored correctly. This can cause false RBF behavior when loading a scene file. If a pose, with zero values for the input and pose values is placed at the end of the pose list the weight driver is unable to tell how many poses there are when loading a scene file.

Successive Pose IDs

When connecting attributes manually without the Weight Driver Editor all connections should be made in successive order, starting at index 0. Indices should not be skipped. When using the editor, this is not an issue, because even if poses get deleted the resulting setup will always have the poses in successive order.

Again, this has to do with Maya’s sparse arrays. Manually skipping one or more indices can lead to a false RBF behavior.