DTI's CAD Supported Filetypes:
Catia files (V4 and V5 - files from Catia V2 through V5 can be used)
.CATPart	V5 Part (geometry) file
.CATDrawing	V5 Drawing file
.CATProduct	V5 Assembly file
.Model	V4
Pro-E files (must be opened by version created by or newer)
.prt.x  (x denotes a number)	Part (geometry) file
.drw.x	Drawing file
.asm.x	Assembly file
SolidWorks files (must be opened by version created by or newer)
.sldprt	Part (geometry) file
.slddrw	Drawing file
.sldasm	Assembly file
Cadkey files
.prt	Part (geometry or drawing) file
.ptn	Pattern (geometry or drawing) file
AutoCad files (must be opened by version created by or newer)
.dwg	Part (geometry or drawing) file
.dxf	Drawing Exchange format
Other CAD package files (import only)
.prt	Unigraphics II : solid part file
.ipt	Inventor : solid part file
.par	Solid Edge : solid part file
.ct	Catia : part file
Import/Export file formats (can usually be exchanged between different platforms)
.igs (iges)	Typically used for wireframe or solid part geometries
.dxf	flat drawings or simple geometries
.stp (step)	for exchanging assemblies; maintains components within file
.sat	for exchanging parts or assemblies; maintains solid geometry
.x_t, .x_b, .xmt_txt, .xmt_bin	Parasolid files; robust translator of solid parts & assemblies
We can also import a large variety of less mainstream files such as: .set, .vda, .neu, ,.cdm, .pdg, .cgm, .stl, .wrl, .mdb, .neu, .icn, .bin
Most CAD packages can import and export .dxf and .igs formats. Sometimes the .dwg format can be used as an import/export file, although this is typically created by AutoCad, and is specific to the version.