Creating an interface block (SysML)
You can create an Interface Block from a Model, Package or Block.
For information about creating an Interface Block on a Block Definition Diagram, click here 
To create an interface block:
1. Right-click the Model or Package or Block that is to own the Interface Block, and select > > > .
Right-click the Block that is to own the Interface Block, and select > > .
2. Type the required name of the Interface Block, and then press the Enter key.
After creating an Interface Block you can specify that it is abstract or encapsulated. For more information see the Related Topics.