Kinematic Properties of Hierarchy Parts
Properties of Rotating Parts
The Endpoints zones set the world coordinates of the endpoints of the axis around which the part pivots. The Pick 
buttons allow you to set the position of an endpoint of the axis with a click in the 3D view. Clicking on this button opens a menu that defines the picking behavior. You can choose whether the endpoint should be placed:
At the location of your click,
At the center of the clicked surface,
At the pivot of the clicked surface.
The 
button switches the position of the endpoints. This can be useful to reverse the direction of rotation around the axis.
The Min and Max angle fields set the limits between which the part can be animated.
The Show in Animation Slider Editor option is checked by default. This allows the animation of this part to be played manually using the Animation Slider Editor in Matter.
Properties of Translatable Parts
The Vector zone allows the endpoints of the translation vector to be provided in world coordinates. The Pick buttons allow you to set the position of an endpoint of the vector with a click in the 3D view. Clicking on this button opens a menu that defines the picking behavior. You can choose whether the endpoint should be placed:
At the location of your click,
At the center of the clicked surface,
At the pivot of the clicked surface.
The button switches the position of the endpoints.
The min and max distance fields limit the distance over which the part can be animated.
The Show in Animation Slider Editor option is checked by default. This allows the animation of this part to be played manually using the Animation Slider Editor in Matter.
Properties of Freely Transformable Parts
In the Settings zone, you can provide the world coordinates of a null’s position. The Pick button allows you to set the position of the null with a click in the 3D view. Clicking on this button opens a menu that defines the picking behavior. You can choose whether the null should be placed:
At the location of your click,
At the center of the clicked surface,
At the pivot of the clicked surface.