When you import a drawing into Revit Architecture, you are importing all the elements, such as blocks and external references (xrefs) from the drawing. (See .) They are all contained inside a Revit element called an import symbol.
You can explode (disassemble) the import symbol into its next highest level elements: nested import symbols. This is a partial explode. A partial explode of an import symbol yields more import symbols, which, in turn, can be exploded into either elements or other import symbols. This is analogous to exploding in AutoCAD with nested xrefs and blocks. For example, you explode an xref into other xrefs and blocks. Those xrefs and blocks can, in turn, be exploded into more blocks and xrefs.
You can also explode the import symbol immediately into Revit text, curves, lines, and filled regions. This is a full explode.
To explode imported geometry
These tools are also available on the shortcut menu that displays when you right-click the import symbol.