MGED performs two basic functions: viewing and editing. The standard viewing capabilities of zooming, slewing, slicing, and rotation are available. Likewise, all the standard editing features are also available. The user easily traverses the hierarchical data structure, applying the editing functions of rotation, translation, and scaling to any position in the hierarchy. The hierarchical structure can be modified and regrouped and regions created and modified. Specific parameter editing can also be applied to the solids to produce any shape solid desired.
For several decades, the production and modification of geometric models suitable for sophisticated engineering analysis has been a slow, labor-intensive procedure. In an effort to improve the response time of geometric models, the Ballistic Research Laboratory (BRL) has developed an interactive model editor for their combinatorial solid geometry modeling system (The BRL-CAD Package). The user interface to the geometry of these models is a program called the Multi-device Graphics Editor (MGED) that is designed to replace the traditional manual method for producing and modifying model databases. Using MGED, the geometric models are interactively viewed, modified, and constructed with immediate visual feedback at each step. When desired, the MGED editor can be operated without the need for explicit numerical input and opens a new dimension in the model building process. MGED has made great gains in reducing the bottleneck in the creation of high resolution geometric models.