What is .XEM file?
Extended model definition created with PowerDesigner, an enterprise modeling program; one or more XEM files may be saved along with a PowerDesigner database (.PDM) file and can be stored on a local hard disk or network drive.
Model definitions associated with a specific model can be viewed by selecting "Model?Extended Model Definitions list." XEM files should not be modified by the user, as they may become unusable.
Recommended Software Programs to open .XEM file