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How to export .stl files from your CAD program?


Virtually all 3D Rapid Prototyping machines and 3D Printers use the STL file format for input.

Almost all CAD programs have a way to save or export to the STL file format. Below follow detailed instructions for most common CAD programs.

Don't forget to check the resulting file with a STL Viewer

List of CAD Programs

Instructions for STL export

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

Note: you can only export 3D solid objects to STL

  1. At the command prompt type "FACETRES"
  2. Set FACETRES to 10The FACETRES system variable adjusts the facet resolution of shaded objects. Valid values are from 0.01 to 10. The higher the value, the better the detail.
  3. Type "STLOUT"
  4. Select the objects
  5. Enter Y or hit Enter for Create a binary STL file? [Yes/No] <Yes>
  6. Enter Filename
  7. Save
Autodesk 3ds Max (3D Studio MAX)
  1. File > Export
  2. Select type StereoLitho *.stl
  3. Enter Filename
  4. Save
  5. Select Binary
  6. OK

More information can be found here.

Bentley Microstation V8
  1. File > Export
  2. Choose file type STL. A dialog box opens.
  3. Set Stroke tolerance to 0.05mm (0.002 in)
  4. Select Binary
  5. Click Export
  6. Enter Filename
  7. Click Save
  1. File > Export > STL...
  2. Enter Filename
  3. Select location
  4. Click button Export STL
Cadkey / KeyCreator
  1. File > Export > STL
  2. Enter Filename > OK
  3. In the options dialog:
    1. Change Format to Binary
    2. Change "Facet Tolerance" if a higher resolution is required

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


The export to the STL format is only possible in the Part Design environment.

If you want to export a complete assembly (CATProduct) as a single stl file, you will have to convert the assembly in the Assembly Design environment to a CATPart as follows:

  1. Select the entire product tree
  2. Tools > Generate CATPart from Product
  3. Enter New Part number
  4. do NOT check: Merge all bodies of each part in one body
  5. OK

Now you can export the CATPart in the Part Design environment.

The accuracy of the STL file depends on the Display accuracy. First set the display accuracy.

  1. Tools > Options...
    1. In the tree select General > Display
    2. select the Performance tab
    3. Under 3D Accuracy select Fixed
    4. Set to 0.02 mm (0.0008 in)
    5. Adjust Curves' accuracy ratio to 0.2
    6. OK
  2. File > Save As
  3. Enter Filename
  4. Select type stl
  5. Save
Creo Direct (Creo Elements/Direct, CoCreate, OneSpace, SolidDesigner)
The Express Edition with some limitations is freely available from PTC
  1. File > Save
  2. Press Select > select the objects (or click All Objects)
  3. Select File Type STL (*.stl)
  4. Click Options
    1. Check Binary
    2. Max Deviation Distance: enter 0.025 mm (0.001 in)
    3. Angle: enter 30°
  5. Enter Filename
  6. Save
Creo Parametric (Creo Elements/Pro, Pro/ENGINEER)
  1. File > Save a Copy
  2. Select type STL > OK
  3. Select Coordinate System Standard
  4. Check Binary
  5. Set Chord Height to 0 (Pro/E changes it to the smallest allowable value)Chord height is the maximum deviation between the facets of the STL file and the model. The unit is the unit of the model. A typical value would be 0.025 mm (0.001 in).
  6. Leave Angle Control at the defaultAngle Control improves detail in smaller radii. Values between 0 and 1.0. The higher the value, the better the detail. Set this value as high as possible.
  7. Enter Filename > OK
  1. File > Export > Rapid Prototype File
  2. Select the part
  3. Select Prototype Device > SLA500 > OK
  4. Set Absolute Facet Deviation to 0.000395
  5. Select Binary > OK
Autodesk Inventor / Mechanical Desktop

You can export individual parts or whole assemblies.

  1. Manage tab > Update panel > Rebuild All
  2. File > Save as > Save Copy As
  3. Select STL
  4. Enter Filename
  5. Select Options
    1. Format > Binary
    2. Units > mm or inches
    3. Resolution > High
  6. Save

More information can be found here.

  1. Right Click on the part
  2. Part Properties > Rendering
  3. Set Facet Smoothing to 150
  4. File > Export
  5. Select .STL
Autodesk Revit
  1. Download the STL Exporter from Autodesk Labs
  2. Unzip and install using the installer for your version of Revit
  3. Load the 3D model and select a view
  4. External Tools > Export
  5. Adjust and scale your model using a STL viewer

The STL Exporter exports one STL unit for every foot (304.8 mm) in your model. So use your calculator and carefully check the result in a STL viewer before 3D printing anything.

  1. File > Export Selected or File > Save As
  2. Select the objects to be exported
  3. Select File Type Stereolithography (*.stl)
  4. Enter Filename
  5. Save
  6. in STL Mesh Export Options
    1. Enter Tolerance 0.02 mm (0.0008 inches) This is the maximum distance between the STL facets and the surface of the model.
    2. OK
  7. Alternatively press Detailed Controls... which opens the dialog box Polygon Mesh Detailed Controls
    1. Set Maximum angle to 30°
    2. Set Maximum distance edge to surface to 0.02 mm (0.0008 inches)
    3. Set Minimum intial grid quads to 16
    4. Check Refine mesh
    5. Leave all other controls at 0 or unchecked
    6. OK
  8. in STL Export Options
    1. Select Binary
    2. Uncheck Export Open ObjectsPrevents that models are exported which are not watertight.
    3. OK
  9. If you get the STL Export Warning dialog, Cancel and fix your modeling errors
Siemens PLM NX (Unigraphics)
  1. File > Export > STLIf you do not see the option, you may not have full menus displayed. Click Tools > Customize. Click the Options tab. Check the box for Always Show Full Menus.
  2. Select Output Type Binary
  3. Set Triangle Tol to 0.025 mm (0.001 in)
  4. Set Adjacency Tol to 0.1 mm (0.04 in)
  5. Set Auto Normal Gen to On
  6. Set Normal Display to Off
  7. Set Triangle Display to On
  8. OK
  9. Enter Filename > OK
Google Sketchup
Google Sketchup cannot export to STL natively. You will have to install a plugin. Here are the possibilities:

Alternatively export to .dae file, then import the .dae (COLLADA) file in Meshlab or Blender and export to .stl file.

Solid Edge (Siemens PLM)
  1. File > Save As
  2. Set type to STL
  3. Click Options
    1. Set conversion Tolerance to 0.025 mm (0.001 in)
    2. Set Surface Plane Angle to 45.0°
    3. Select Binary
    4. OK
  4. Enter Filename
  5. Save
  1. File > Save As...
  2. Set type to STL(*.stl)
  3. Click Options...
    1. Output as: check Binary
    2. Unit: > Millimeters or Inches
    3. Resolution > Fine
    4. OK
  4. Enter Filename
  5. Save
SolidWorks Student Design Kit
  1. File > Save As...
  2. Set type to eDrawings(*.eprt)
  3. Click Options...
    1. Check Allow export to STL for Parts & Assemblies
    2. OK
  4. Enter Filename
  5. Save
  6. Open part in eDrawings
  7. File > Save as… > select type STL Files (*.stl)
  8. Save
  1. File > Save As
  2. Set type to STL
  3. Save

Vectorworks only exports the current layer to STL. Please read Tips for Users of VectorWorks.pdf on how to merge the layers into one layer.

  1. File > Export > Export Stereolithography (3D Only)
  2. In Export STL Options
    1. check File Type ASCII
    2. adjust the slider Export Quality towards the middle
    3. OK
  3. Enter Filename
  4. Save