Once a new block node has been created on the navigation tree, it becomes the "Active" group of the project workspace, which is always displayed in bold letters. Then you can start drawing new objects under that node. Any block group can be made active by right clicking on its name in the navigation tree and selecting the '''Activate''' item of the contextual menu.
It is recommended that you first create block groups, and then draw new objects under the active block group. However, if you start a new EM.Terrano project from scratch, and start drawing a new object without having previously defined any block groups, a new default impenetrable surface group is created and added to the navigation tree to hold your new CAD object. Â You can always change the properties of a block group later by accessing its property dialog from the contextual menu. You can also delete a block group with its objects at any time.
[[Image:PROP15.png|thumb|400px|EM.Terrano's Domain Settings dialog.]]