EP3 is a user-interface for EnergyPlus developped over many years.  EP3 allows you to create models quickly and efficiently.  It also allows you to quickly update and make changes to building geometry.  Information for EEMs are almost limitless and information is stored in the same parent file.  Do you need to make a change in a base schedule?  The change propagates through to all EEMs.

A number of modules are available:

Building Geometry, Constructions and Internal Loads - comprehensive tool for creating complex building geometry, supports creation of Spaces, Zones, shading, constructions, and internal loads.  Capabable of automatically creating fenestration based on window to wall ratio.  Window placement and window to wall ratio can be changed in each EEM

Building Geometry, Constructions and Internal Loads IDF importer - import building geometry, constructions and internal loads for IDF files.  Currently supports files created using World Coordinate System.

HVAC - create simple or complex HVAC configurations of HVAC components.  Create multiple HVAC system configurations and turn them on and off depending on the EEM

HVAC IDF Importer (under development)