Previous Document Next Document

Relations > Joint constraints > Ball joint constraint

Ball joint constraint


This relation creates a position and rotation connection between two objects that allows for rotation around all three axes. This type of joint is similar to an ankle joint, a universal joint, or a joystick. It allows one object to pivot freely around another. You can also limit the amount of freedom in a constraint by setting angle limits. For example, the joystick can pivot freely but it cannot move lower than its base.


Example: Applying a ball joint constraint
  1. Create a sphere.
  2. Create a cylinder, and set its height to 4 and a width to 1.
  3. Multi-select the cylinder and the sphere, in that order.
  4. Choose Relations > Joint Constraints > Ball.
  5. Choose View > Display > Constraints.
  6. A blue sphere appears to represent the ball joint.

  7. Turn off the Lock button. This will enable you to offset the cylinder's position. Translate the cylinder up on the Y axis.
  8. To test the constraint, turn on the Lock button and translate the cylinder in all viewports. It is constrained to the sphere and can only rotate around the ball joint that you created. Translate the sphere to verify this. You could also select the ball joint and offset it if you wanted to change the actual rotation point.

  9. Select the constraint and turn on Enable joint limits in the Parameter Editor.
  10. This will constrain the cylinder to move freely around a certain opening.

  11. Adjust the maximum limit angle, and notice the opening in the ball joint widening or narrowing.
  12. By default it is the X axis of the cylinder that is constrained. Change Constrained axis to
    0, 1, 0 (the Y axis). Translate the cylinder and notice how it moves freely within the opening you set with the Maximum limit angle.

Ball Joint Constraint Parameters

Active

Toggles the constraint on and off.

Weight

Determines the weight the constraint in relation to other constraints acting on the same object.

Position

Determines the position in X, Y, Z (in units) of the ball joint, around which the object will rotate.

Orientation

Sets the orientation of the ball joint. You can also rotate the constraint interactively in the viewport.

Joint angles

Determines the current angle of the constrained object.

Enable joint limits

Sets a maximum angle limit. Turning on this option displays the maximum angle value, which determines how much the constrained object can rotate, as well as its axis.

Constrained axis

Chooses the axis of the object that the joint limit will affect. By default it is the X axis.

Maximum limit angle

Sets the maximum angle in degrees.


See also:

Unlocking constraints

Using weight to control multiple constraints

"To view the constraint in the viewports:"

Previous Document Next Document