# Assign geometry/surface condition
![The "Assign geometry/surface condition" icon](img/pre_settings.png)
This command allows the user to select elements/surfaces that are physical walls, for the calculation of
pressure and drag force.
![](img/p4_cond_geometry.png)
The condition can be assigned over lines or surfaces.
* **Group** : This option allows users to assign the line/surface to a different group for post-processing.