You can use Autodesk Navisworks to combine design files together into complex datasets.
Autodesk Navisworks enables you to combine design files together by bringing geometry and metadata from supported external files into the current scene. Autodesk Navisworks automatically aligns rotation and origin of models, and rescales the units in each appended file to match display units. If the rotation, origin, or units are incorrect for the scene, you can manually adjust them for each of the incorporated files.
For multi-sheet files, you can also bring geometry and data from internal project sources, that is 2D sheets or 3D models listed in the Project Browser, into the currently open sheet or model. See Add Geometry and Metadata to the Current Sheet/Model.