You can define a boundary condition by selecting one of the common types listed in the symmetry/antisymmetry/encastre boundary condition editor.
To create or edit a symmetry/antisymmetry/encastre boundary condition:
Display the symmetry/antisymmetry/encastre boundary condition editor using one of the following methods:
To create a new symmetry/antisymmetry/encastre boundary condition, follow the procedure outlined in “Creating boundary conditions,” Section 16.8.2 (Category: Mechanical; Types for Selected Step: Symmetry/Antisymmetry/Encastre).
To edit an existing symmetry/antisymmetry/encastre boundary condition using menus or managers, see “Editing step-dependent objects,” Section 3.4.13. You can edit the symmetry/antisymmetry/encastre boundary condition only in the step in which it was created.
If you are creating the boundary condition in a buckling step, select the Use BC for option that specifies the calculations for which you want the boundary condition used. For more information, see “Boundary conditions,” in “Eigenvalue buckling prediction,” Section 6.2.3 of the Abaqus Analysis User's Guide.
By default, the global coordinate system is used to define the boundary condition. To change the coordinate system in which the boundary condition is applied, click 
for the CSYS option and do one of the following:
Select an existing datum coordinate system in the viewport.
Select an existing datum coordinate system by name.
From the prompt area, click Datum CSYS List to display a list of datum coordinate systems.
Select a name from the list, and click OK.
Click Use Global CSYS from the prompt area to revert to the global coordinate system.
Select one of the following options:
| XSYMM | Symmetry about a plane X = constant (U1 = UR2 = UR3 = 0). |
| YSYMM | Symmetry about a plane Y = constant (U2 = UR1 = UR3 = 0). |
| ZSYMM | Symmetry about a plane Z = constant (U3 = UR1 = UR2 = 0). |
| XASYMM | Antisymmetry about a plane with X = constant (U2 = U3 = UR1 = 0;Abaqus/Standard only). |
| YASYMM | Antisymmetry about a plane with Y = constant (U1 = U3 = UR2 = 0;Abaqus/Standard only). |
| ZASYMM | Antisymmetry about a plane with Z = constant (U1 = U2 = UR3 = 0;Abaqus/Standard only). |
| PINNED | Pinned (U1 = U2 = U3 = 0). |
| ENCASTRE | Fully built-in (U1 = U2 = U3 = UR1 = UR2 = UR3 = 0). |
Click OK to save your data and to exit the editor.
