3D Printing and Rapid Prototyping – What File Types Should I Use?

CAD files have a myriad of formats and corresponding file extensions (example: filename.extension.) With all those formats out there, what is best for you to use?

CAD files for 3D printing generally fall into two categories: parametric files (equation driven files that are fully defined – i.e. a circle is actually a circle) and mesh files (made of points and triangles – i.e. a circle is thousands of tiny triangles.)

Parasolids tend to be the best files to use because your 3D printing service provider should have the expertise to make sure your final export will have no errors. Mesh files tend to work  too, but many times require a great deal of fixing.

Mesh files can fit into two categories, files with surface color (renderings) and those without.

Please keep in mind that many mesh files (particularly STLs) never have any units attached to them, so if printing a file as a mesh, please tell your provider whether or not it was designed in milimeters, centimeters or inches.

The list below breaks down categories of file type and lists them in the order of preference to make the printing process as seemless as possible for the customer and service provider. 

Engineering and Design (parametric, boundary representation files)

1. SolidWorks (.SLDPRT, .SLDASM, .SLDDRW)
2. Inventor (.IPT, .IAM)
3. Parasolid (.X_B, .X_T)
4. STEP (.STP, .STEP)
5. IGES (.IGS, .IGES)
6. Rhino (.3DM)
7. AutoCAD (.DXF, .DWG 2010 or earlier preferred)

Color 3D Printing (mesh files with color and/or texture information)

1. ZPR
2. OBJ (must include MTL file and texture maps)
3. FBX
4. 3DS
5. PLY
6. 3DM
7. WRL

Standard 3D Printing (mesh files)

1. STL
2. OBJ
3. PLY
4. 3D DXF or 3D DXF (2010 or earlier preferred)
5. 3DM
6. SKP (SketchUp*)

*While we can and do work with SketchUp files, extra engineering fees may apply to convert them into usable geometry.