Joint
Joint

Joint objects are used to join two physics bodies together . For a much detailed explanation about joints, check these pages from Solar2D API
Before selection the Set joint properties option, make sure you select a layer already set as a body. Doing so, it will open the following window:

Properties panel:
Information about the current layer content will appear in the top of the window (position and size). It is important to understand that animations will always use the current position of the layer, group or page as starting point.
-
Connect with: lists all other bodies. Select the one touching the main body (in this example ball);
-
Joint Type sets which kind of joint will be used. It can be:
- Pivot: joins two bodies at an overlapping point;
- Distance: joins two bodies at a fixed distance;
- Piston: joins two bodies along a single, restricted axis of motion, like the pistons or a shock absorber in a car;
- Friction: a special kind of pivot joint that resists motion, and is therefore “sticky”;
- Weld: a weld joint “welds” two bodies together at a specified point in world coordinates;
- Wheel: combines a piston and a pivot joint, like a wheel mounted on the shock absorber of a car;
- Pulley: attaches two bodies with an imaginary rope whose length remains constant: if one body is pulled down, the other one will move up;
-
Joint connection point X and Y: fields to receive the X,Y position where the two bodies (the selected layer and the connect with) joints;
Optional parameters
these parameters may not work for all joint types. However, some of them are mandatory for some joint types. For a detailed explanation of each field, check
https://docs.coronalabs.com/guide/physics/physicsJoints/index.html