Posing >
Adjust a joint’s region of influence

Sometimes a joint’s default region of influence, also referred to as the joint weight, does not produce the desired results when the model component is deformed using the Pose tool. The joint weight (region of influence) can be modified in an interactive fashion using the Weights tool. This can aid in improving the results when you deform the component.

The Weights tool works exactly like the other paint and masking tools within Mudbox by letting you stroke on the surface of the model to add or subtract weighting color in areas of the model you want affected by the selected joint. Adding or subtracting weight color to vertices on a model increases or decreases the amount of influence the active joint has on those vertices when it’s deformed using the Pose tool.

- Remove weight color on vertices affected by the joint when an associated model component deforms unexpectedly.
- Add weight color to vertices when they don’t deform as fully as expected.
  TipIf the Weights tool is used immediately after a joint transformation the vertex positions will update their positions based on the weight changes. This makes it easy to assign the correct weights if you don’t get the expected deformation.

1. Ensure that the joint is selected so the weighted region you want to adjust appears on the model.

   The weight color appears for a joint immediately after it is created using the Create Joint tool, or when the joint is selected using the Pose tool.

   NoteYou can also select the joint using the Object List by expanding the joint hierarchy beneath skeleton node for the model and clicking a joint name in the list.
2. In the Pose Tools tray, select the Weights tool.

3. In the 3D View, stroke across the model using the Weights tool on the vertices that you want the joint to have an increased influence on when the model is deformed.
   NoteIt is currently not possible to adjust paint weights on vertices that are already affected by more than four joints as might occur when importing a rigged model from another 3D application. For more information, see Import models with existing joints.

   To remove paint weight color on vertices, press the Ctrl key as you stroke to remove Weight color in those regions. If you want the tool to remove paint by default, turn on the Invert property in the Weights property window.

   If the model is in mid-pose, painting weight color or using the smooth feature (Hotkey: Shift) to blur the weight color (will automatically update the vertex positions to reflect the adjusted weights value, provided you have not exited the pose tools to use a sculpt or paint tool. (The pose is referred to as being uncommitted in this situation). For more information, see Committed vs. uncommitted poses. Otherwise, the vertices will update to reflect the new weight values the next time the joint is posed.

   Use the camera navigation keys to dolly and tumble the model as you use the tool. If you accidentally miss removing any weight color on an area you do not want affected by a joint it will become obvious when using the Pose tool as some vertices will still move when the model component is deformed.

   TipIf the brush ring for the Weights tool is scaled larger than the model component, it will actually wrap around the model when painting which can reduce the amount of camera rotation that is required.

   Just like other paint tools, you can adjust the Weights properties such as Size, Strength, and Mirror to suit your requirements.

   The color for the joint weights can be customized in the color preferences (Windows > Preferences > Color) by adjusting the Joint Weight color.

   NoteKeep in mind that adjusting the weights is one method for improving the final results when posing and deforming your models. The sculpt tools can and should be considered for quickly adjusting unwanted folds and bulges that can occur.

Related topics

Posing overview

Pose Tools tray

Create a joint

Pose a model component

Adjust a joint’s pivot location

Import models with existing joints

Troubleshoot posing