CAD to STL

Get Ready to 3D Print your CAD File

Find below step-by-step instructions for converting various CAD file formats to STL for printing on Objet 3D printers.

Need to fix an STL? Download here.

McNeel Rhino

  1. File > Save As
  2. Select File Type to STL
  3. Select File Name > Save
  4. Select Binary
  5. Select Detail Controls from Mesh Options
  6. Max Angle = 20, Max aspect ration = 6, Min edge Length = 0.0001
  7. OK

McNeel Rhino - version 3 and later

Rhino enables extensive control of STL properties when saving designs as STL files.

Because Rhino software is surface-based, the complete model design (even if an assembly) is saved as a single STL part.

Saving a model design in STL format

  1. Open the model design in Rhino.
  2. From the File menu, select Save As. The Save dialog box opens.
  3. In the File name box, enter a name for the new STL file.
  4. In the Save as type box, select Stereolithography [*.stl].
  5. Click Save.
  6. In the STL Mesh Export Options dialog box, set the STL tolerance – the maximum distance allowed between the surface of the design and the polygon mesh of the STL file.
    • In the Polygon Mesh Detailed Options dialog box, set the STL tolerance in the field labeled Maximum distance, edge to surface, as shown in the figure. If you do not know the other settings appropriate for your model design, try these:
    • Maximum angle – clear
    • Maximum aspect ratio – clear
    • Maximum distance edge to surface (Tolerance) – less than half of the printer’s resolution. For example, the setting shown in the figures above (0.01 mm) is a good setting for printing models at a resolution of 30 ?m (0.03 mm).
  7. Click OK.
  8. In the STL Export Options dialog box, set the file type as Binary and click OK.

If the Export open objects check box is selected, STL files will be created for each of the objects currently open. If this check box is cleared, an STL file is created for the selected object.

Important: STL files are suitable for 3D printing if the models they describe are "watertight" - that is, they do not contain holes or gaps. If the following message appears, click Cancel and fixd the model design (see image FIgure 30) before saving it as an STL file.

Troubleshooting Model Designs

If a model design contains holes or gaps, it is not suitable for 3D printing. Before saving it as an STL file, you must make it “watertight.”

To close holes and gaps in a model design:

  1. Select the entire object.
  2. From the Edit menu, select Join.
  3. or – Click the Join icon on the side toolbar. This command reduces the number of surfaces and fits them together tightly. (The entities are not fused together into one unit.) The message in the command bar indicates this.
  4. Select the object. You can select the entire object, but to save time, you may select only the problematic entity.
  5. From the Tools menu, select Polygon Mesh > From NURBS Object. or – Click the Mesh from Surface/Polysurface icon on the side toolbar. The Polygon Mesh Options dialog box opens.
  6. Click Detailed Controls… The Polygon Mesh Detailed Options dialog box opens.
  7. Enter the same settings as before and click OK.
  8. Select the entire object.
  9. From the Tools menu, select Polygon Mesh > Weld.
  10. In the command bar, type 180 for the angle tolerance, and press Enter. With an angle tolerance of 180, the Weld command always merges adjacent triangle points.
  11. From the Tools menu, select Polygon Mesh > Unify Normals. This setting unifies the normals of all triangles, so that they have the same definition for “up.”
  12. To validate that the object is watertight, type SelNakedMeshEdgePt in the command bar, and press Enter. If the resulting object contains holes or gaps, the mesh point is highlighted in the display.
  13. Repeat the Save As procedure