I need to add CAD data into arcmap but it does not have spatial reference. Thus, when I add the cad file it does not spatially align with my other layers. Does anyone know the solution to this problem.
If it's in a 'known' coordinate system like a UTM zone, you can define its coordinate system with the Define Projection tool or its property page in ArcCatalog. If you don't know its coordinate system or it's a 'local' coordinate system, you'll have to georeference it. You may want to start here in the help: About georeferencing CAD datasets
