ProtoCAM: Additive Manufacturing, 3D Printing and Rapid Prototyping.

How to Prepare a CAD File for Additive Manufacturing

July 1, 2015

At ProtoCAM, we can create rapid prototypes and additive manufacturing projects from a number of file formats.

We accept files from any CAD package, provided the geometry is exported into an STL (stereolithography) file format – the standard for the rapid prototyping industry. STL is ideal as it approximates the surface of a parametric solid model with a mesh of triangles, but, in addition, we also accept these file formats:

  • Pro/ENGINEER (*.PRT.*)
  • SolidWorks (*.SLDPRT)
  • STEP (*.STEP/*.STP)
  • Binary Parasolid (*.X_B)
  • Parasolid (*.X_T)
  • Neutral (*.NEU)
  • Rhino 3D (*.3DM)
  • IGES (*.IGES/*.IGS)

How do I export an STL file for additive manufacturing?

STL files suitable for rapid prototyping can be exported from any standard CAD package. Instructions for many leading software suites follow.


  1. File
  2. Export
  3. Save As > STL
  4. Enter File Name
  5. Save


Your design must be a three-dimensional solid object to output an STL file.

Type these commands in AutoCAD’s command line:

  1. Set DISPSILH to 1
  2. Set ISOLINES to 0
  3. Set FACETRES to 10
  4. Relocate the object to the positive X-Y-Z octant
  5. Use the STLOUT command to export an STL file. (AMSTLOUT for AutoCAD Desktop files)

Autodesk Inventor

The detail settings for STL Output are stored in the registry.  Information on changing the detail level can be found at Autodesk’s website, under the title “Set accuracy for exporting STL files from Autodesk Inventor software” and ID TS64378.

  1. Go to the File menu, then select the Save Copy As… choice
  2. Select STL from the Types drop-down
  3. Click the Options button, and choose the High detail level
  4. Click the Save Button.


  1. Go to the File menu, then Export, then STL
  2. Type in a filename and select OK
  3. A new window will appear with options for the export
  4. Change Format to Binary
  5. Change Facet Tolerance if a higher resolution STL file is desired

Additional export tolerance options are in the Solids99 Configuration window accessed from the Tolerance section of Configuration.


  1. File > Export > Rapid Prototype File > OK
  2. Select the part to be prototyped
  3. Select prototype device > SLA500.dat > OK
  4. Set absolute facet deviation to 0.000395
  5. Select Binary > OK


  1. Save Copy As
  2. Select STL
  3. Choose Options > Set to High (for highest quality surface)
  4. Enter File Name
  5. Save


  1. Select Part Properties then Rendering
  2. Set Facet Surface Smoothing to 150
  3. Select File then Export
  4. Select .STL

Mechanical Desktop

  1. Use the AMSTLOUT command to export the STL file. The following command line options affect the quality of the STL and should be adjusted to produce an acceptable file.
  • Angular Tolerance – This command limits the angle between the normals of adjacent triangle. The default setting is 15 degrees. Reducing the angle will increase the resolution of the STL file.
  • Aspect Ratio – This setting controls the Height/Width ratio of the facets. A setting of 1 would mean the height of a facet is no greater than its width. The default setting is 0, ignored.
  • Surface Tolerance – This setting controls the greatest distance between the edge of a facet and the actual geometry. A setting of 0.0000 causes this option to be ignored.
  • Vertex Spacing – This option controls the length of the edge of a facet. The default setting is 0.0000, ignored.

Pro/ENGINEER or Creo

We are able to accept native Pro/E and Creo files, so please consider sending us the .PRT file instead of an STL.

  1. Select File, then Save As
  2. Pick .STL from the Save As Type dropdown menu
  3. Input 0 for the chord height
  4. Leave Angle Control at default
  5. Select OK


  1. File > Export > Model
  2. STL
  3. Set chord height to 0. The field will be replaced by minimum acceptable value.
  4. Set Angle Control to 1
  5. OK

ProE Wildfire

  1. File > Save a Copy > Model
  2. Change type to STL (*.stl)
  3. Set Chord Height to 0. The field will be replaced by minimum acceptable value.
  4. Set Angle Control to 1
  5. OK


  1. File > Save As
  2. Select File Type > STL
  3. Enter a name for the STL file
  4. Save
  5. Select Binary STL Files


  1. Select the File menu, then External, then Save STL
  2. Select Binary mode
  3. Select Part
  4. Type in your Filename
  5. Enter 0.01 mm for the Max Deviation Distance
  6. Select OK


  1. Select File, then Save As
  2. Set Save As Type to STL
  3. Select Options
  4. Set Conversion Tolerance to 0.001 in or 0.0254 mm.
  5. Set Surface Plane Angle to 45.00°
  6. Select Save


We are able to accept native SolidWorks files, so instead of creating a STL, please consider sending us the SLDPRT (and any appropriate drawings or assemblies).

  1. Select File, then Save As…
  2. Select STL (*.STL)”
  3. Select Options
  4. Set Resolution to Fine
  5. Select OK
  6. Select Save


  1. File > Save As
  2. Set Save As Type to STL
  3. Save


  1. Select File, then Export, then Rapid Prototyping
  2. Set Output Type to Binary
  3. Set Triangle Tolerance to 0.0025
  4. Set Adjacency Tolerance to 0.12
  5. Set Auto Normal Gen to On
  6. Set Normal Display to Off
  7. Set Triangle Display to On

How can I send my file for additive manufacturing?

You can send a file to ProtoCAM very quickly by one of several methods. Please call us at 610-261-9010 if you have any problems or questions.

When uploading your file(s), please consolidate and compress them with a utility such as WinZip, and include a note indicating quantity, material and finishing preferences for each part.