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

Autodesk Inventor allows you to save both individual parts and assemblies in STL format, at all design levels.

Phase 1: Saving a model design in STL format
To save an Autodesk Inventor model design as an STL file:

  1. From the Tools menu, select Rebuild All. This ensures that the design data contains recent changes, and that it is not corrupt.
  2. From the File menu, select Save Copy As... > To Save copy as dialoge box opens
  3. In the Save as type field, select STL Files (*.stl), and click Options. The STLOut Save Options dialog box opens.
  4. Select High and click OK.
  5. In the Save Copy As dialog box, click Save.
  6. Note: To change the values associated with each of the resolution settings (High/Medium/Low) you need to edit the Windows registry.