Today, CAD (Computer-Aided Design) is broadly used across many industries, including aerospace, automotive, shipbuilding, plant design, civil engineering, construction, and more. To satisfy the unique needs of each industry, a wide range of CAD developers have launched their own software solutions.

As a result, we now have a diverse array of filename extensions used in CAD. However, there is no CAD system that can import every file extension; most CAD systems can only import certain extensions. So, let’s take a look at which file extensions can be imported by major CAD systems. When dealing with a CAD data file, you can generally categorize it into one of these three types:

Native Files (Proprietary Format)

These are original filename extensions defined for use within specific CAD software. Because they are not common standard extensions, other CAD systems generally cannot import them. However, some CAD software offers special features or add-on options to enable these imports.
(Examples: .CATPart for CATIA, .prt for NX, .sldprt for SOLIDWORKS)

Solid Kernels’ File

Just as each CAD system has its own native extensions, each solid kernel—the core “engine” a CAD system uses to shape solid models—has its own specific extensions. The two leading geometric kernels integrated by most CAD systems are:

• Parasolid by Siemens
• ACIS by Spatial

When a neutral file such as a STEP extension is imported into a Parasolid-powered or ACIS-powered CAD system, it can be exported back out using each solid kernel’s native extension. You will notice that the file size is significantly smaller when you choose extensions composed of binary data rather than text data.

	Extension	File size (KB)	Notes
Original File
STEP	.stp	57,334
Solid Kernel
Parasolid	.x_t	63,525	Can be opened in text editor, human-readable (text data)
	.x_b	41,506	Non-human-readable (binary data)
	.xmt_txt	63,525	Can be opened in text editor, human-readable (text data)
	.xmt_bin	41,506	Non-human-readable (binary data)
ACIS	.sat	42,355	Can be opened in text editor, human-readable (text data)
	.sab	N/A	Non-human-readable (binary data)

Neutral Files

These are internationally shared, common filename extensions that most CAD systems support.

• IGES and STEP format extensions are the most popular types.
• The JT format extension is widely used in specific CAD environments.
• STL and OBJ format extensions are used for modeling with polygons, rather than mathematical curves like splines.
  (Examples: .igs/.iges from IGES, .stp/.step from STEP, .stl from STL, .obj from OBJ)

The list of filename extensions sorted by CAD

Here is a list of filename extensions sorted by CAD. Depending on your CAD system, special features or options may be required to import certain extensions.

Got files that your CAD doesn’t support importing?

If you run into compatibility issues, just check our website and try our product: spGate.

CAD System	Format Type	Extension	Format Name
CATIA V5-6R2026 (V5R36)	Proprietary Format	.CATPart, .CATProduct, .CATDrawing	CATIA V5
		.model	CATIA V4
		dxf, .dwg	AutoCAD
	Neutral File	.igs	IGES
		.stp, .step, .stpx, .stpxZ, .stpZ	STEP
NX 2506	Proprietary Format	.prt	NX
		.asm, .par, .psm, .pwd	Solid Edge
		.dxf, .dwg	AutoCAD
		.CATPart, .CATProduct, .CATShape, .cgr	CATIA V5
		.model	CATIA V4
		.sldprt, .sldasm	SOLIDWORKS
		.prt	Creo/ProE
	Solid Kernel	.x_t, .xmt_txt, .x_b, .xmt_bin	Parasolid
		.sat, .sab	ACIS
	Neutral File	.igs, .iges	IGES
		.stp, .step, .stpx, .stpz, .stpxz	STEP
		.jt	JT
		.stl	STL
		.obj	OBJ
		.3mf	3MF
		.ifc	IFC
SOLIDWORKS 2026	Proprietary Format	.sldprt, .sldasm	SOLIDWORKS
		.cgr	CATIA Graphics
		.prt, .asm	Creo/ProE
		.3dm	Rhino
		.par, .psm, .asm	Solid Edge
		.prt	NX
		.ipt, .iam	Inventor
		.dxf, .dwg	AutoCAD
	Solid Kernel	.x_t, .xmt_txt, .x_b, .xmt_bin	Parasolid
		.sat	ACIS
	Neutral File	.igs, .iges	IGES
		.stp, .step	STEP
		.vda	VDAFS
		.wrl	VRML
Creo 12.0	Proprietary Format	.prt	Creo/ProE
		.CATPart, .CATProduct	CATIA V5
		.ipt, .iam	Inventor
		.prt	NX
		.3dm	Rhino
		.par, .psm, .asm	Solid Edge
	Solid Kernel	.x_t, .xmt_txt, .x_b, .xmt_bin	Parasolid
		.sat	ACIS
	Neutral File	.igs	IGES
		.stp	STEP
		.stl	STL
		.obj	OBJ
		.vda	VDAFS
		.wrl	VRML
CADMeister 2025	Proprietary Format	.cprt, .casm	CADMeister
		.CATPart, .CATProduct	CATIA V5
	Solid Kernel	.x_t, .xmt_txt, .x_b, .xmt_bin	Parasolid
	Neutral File	.igs, .iges	IGES
		.jama, .jm	JAMA
		.stp, .step	STEP
		.stl	STL
		.jt	JT
		.cfio	CFIO
CAM-TOOL 22.1	Proprietary Format	.gmd	CAM-TOOL
		.dxf, .dwg	AutoCAD
		.CATPart	CATIA V5
		.prt	NX
		.sldprt	SOLIDWORKS
	Solid Kernel	.x_t, .x_b	Parasolid
	Neutral File	.igs, .iges	IGES
		.stp, .step	STEP
		.stl	STL