Main Article: Stud
Studs relate most to the connectors on LEGO bricks. They appear to be bumpy, but are 2D.
Main Article: Inlet
Inlets are relate to the bottom of a LEGO brick. Inlets will only connect to studs, weld, and universal.
Main Article: Smooth (Surface)
Smooth has no texture seen. It is plain. It comes too as Smooth without Outlines, which removes outlines from certain brick if they are on.
Main Article: Weld
Weld is the strongest, and will hold anything. They appear as Xs on the part. Weld does not always need to be anchored to stay still.
Main Article: Glue
Glue is the second strongest, and can only hold a ball though.
Main Article: Universal
Universal is a combination of stud and inlet. It will connect to inlet and stud.
Main Article: Hinge
Hinge is a non automatic motor. It will only spin by gravity. It is the thing used to connect wheels to VehicleSeats.
Main Article: Motor (Surface)
Motor is automatic, if put on Constant. If you connect another brick, it will spin if unanchored.