Setting a joint limit restricts the range of movement allowed for an actor during the simulation in Behavior. A joint limit is usually used on a bone for the character dynamics rig setup in Behavior for solving IK on the legs when an actor follows an uneven terrain. However, you can also set joint limits on other objects in the simulation (prop actors); for example, you can specify the limit to which a door is allowed to swing open. The joint limits are defined with respect to the node’s home pose.
When you save the actor in a dotXSI file (see Saving the Behavior-Ready Actor), the joint limit is converted to a custom property that Behavior references to ensure that the actor’s movements are allowed.
You can set joint limits only on Behavior-ready actors.
To set a joint limit
1. Make sure that the actor is generated (see Generating a Behavior-Ready Actor).
2. Reset the actor to its home pose for the best results (choose Actor > Go to Home).
3. Select the node on the actor to which you want to set a joint limit and choose Node > Add Joint Limit from the Behavior toolbar.
4. In the property editor that appears, set the limits of the node’s allowed movement.
- Select Use for Bvr IK if you want the joint limit to be used to restrict the joint’s movement during IK locomotion activities. This is usually used for a character’s knee joints.
- The Min/Max parameters let you set the limit in degrees of the node’s minimum/maximum movement along its local X, Y, and Z axes.
Drag the Min/Max sliders to see the node interactively move to that angle, or enter a value in the text boxes. Make sure that the range of motion you specify accommodates any animation that you create for the actor.
To remove the joint limit
1. Select the node on the actor on which you’ve set a joint limit.
2. Choose Node > Remove Joint Limit from the Behavior toolbar.
The joint limit information is removed and the node returns to its home pose (you may have to move the mouse or click the node first).
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