Use boundary conditions to communicate engineering assumptions about support conditions to analysis software packages.
You can apply point, line, and area boundary conditions to your analytical model. Click Analyze tab 
Analytical Model panel 
(Boundary Conditions) To access the boundary condition tools. 
Analytical Model panel (Boundary Conditions) To access the boundary condition tools. - Click Modify | Place Boundary Conditions tab Boundary Conditions panel
(Point) 
(Line) - (Area)