Geometry Import Fails  —  Ansys Workbench leverages a running CAD session to update models if one exists. If you change the geometry source to a file that cannot be opened in the running session, the update will fail with an unable to activate document error. Some reasons this may occur are if the new model is from a version of the CAD system later than the one running or if another file of the same name is already opened in the CAD from another directory.

Length Units When Changing Geometry Sources  —  The length units of loads and boundary conditions are based on the unit of the imported model in Mechanical. When the source geometry is changed to another model which uses a different length unit than the first, then loads, boundary conditions, and non-associative coordinate systems in Mechanical will scale to match the new length unit of the imported geometry. This may be observed when importing a model into Mechanical, then later choosing to edit the geometry in DesignModeler. If the DesignModeler session's length unit is different than the original CAD model's length unit, then any existing loads or boundary conditions in Mechanical that were defined for the original CAD model may get scaled.