At present, if you want to combine drawings into one single DWG, it has to be combined manually or by importing each drawing as a block/xref.
This Add-in will make your work easier. You can merge drawings multiple times and choose the position of the drawing in the model space.
Other features:
– You also can convert all raster images to OLE objects in the drawing.
– Convert object color to layer color.
– Export Layer information to a text file.
– Convert all raster images to OLE objects in the drawing