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Relations > Joint constraints > pin joint

Pin joint constraint


This relation creates a position and rotation connection between two objects that allows for rotation around a single axis. This type of joint is similar to a knee joint, or the hinge of a door.


It allows you to pivot one object around another.The object can pivot all the way around the joint or you can limit its freedom by setting angle limits.


Another example of a pin joint is movie clapper or a cigarette lighter where the top cube is constrained to rotate around the bottom cube. If you move the bottom cube, the top will follow it.

To apply a pin joint constraint:
  1. Multi-select the object that will pivot and then the object to which it will be constrained, in that order.
  2. If the objects are positioned correctly, turn off the Lock button to keep that offset.
  3. Choose Relations > Joint Constraints > Pin.
  4. Choose View > Display > Constraints.
  5. The constraint icon appears in the viewport. It is a blue cylinder representing the hinge-like pin joint.

  6. Turn on the Lock button.
  7. When you translate the constrained object, it rotates around the hinge.

  8. To change the position and direction of the hinge, translate and rotate the pin constraint. To select the pin constraint, click the blue constraint icon in the viewport, or select the constraint under the constrained object in the World Explorer.
  9. When you translate the constrained object, it now rotates around the hinge, in its new position and axis.

Pin Joint Parameters

Active

Toggles the constraint on and off.

Weight

Determines the weight of this constraint in relation to others constraints on the same object.

Position

Determines the position of the hinge in X, Y, Z (in units).

Axis

Determines the orientation of the hinge relative to the absolute X Y Z axes. By default the hinge rotates around the leader's X axis. If the leader's orientation is 0 0 0, then the pin's axis is 1 0 0. You can set it to the Y axis (0 1 0) or Z axis (0 0 1), or you can rotate the constraint in the viewport, to change its axis.

Joint angle

Displays the current angle of the follower object.

Enable angle limits

Sets minimum and maximum angle values, which determine how much the follower object can rotate.

Minimum angle
limit

Sets the minimum angle in degrees when Enable angle limits is turned on.

Maximum angle limit

Sets the maximum angle in degrees when Enable angle limits is turned off.


See also:

Unlocking constraints

Using weight to control multiple constraints

"To view the constraint in the viewports:"

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