How to export geometry as a CAD part (STEP or Parasolid)


Convert a Topology Optimized part into a CAD format and export it to a CAD program.  

Note: nTopology is capable of exporting Implicit or Mesh parts to STEP or Parasolid formats. This ability enables you to integrate nTop's robust geometry kernel into CAD workflows. Topology optimization workflows produce the most useful results, but the same process applies to more complex geometry (not including lattices).

Keep in mind that exceedingly faceted geometry (like lattices) and periodic structures are challenging for traditional CAD programs. Read this article, "What are the limitations of exporting lattice structures to CAD?" and Quadrangulate mesh fails when meshing my lattice to learn more. 

Applies to:

  • Export to CATIA
  • Export to ANSYS
  • Export to PTC Creo
  • Export to Siemens NX
  • Export to Solidworks


1. Convert to a Mesh: Convert your topology optimized part to a mesh. 

2. Refine Mesh: Refine your mesh by using Remesh Surface, Simplify by Threshold, Simplify by Amount, or other simplification methods. This step allows for easier conversion to a quad mesh. Make sure your mesh has no meshing errors in it. Take a look at these articles for tips on refining and creating a mesh: 

3. Quad Mesh: Convert the refined Mesh to a quad mesh by using the Quadrangulate Mesh block. The quad mesh allows for easier and faster conversion to a CAD Body format. 

  • A quad mesh is not just a step for converting, but also a very useful model itself. The mesh can be exported into other systems by using the Export Mesh block. 
  • If you encounter errors when converting to a Quad Mesh, check out this article. 


4. Optional: Use a Refine Mesh block to refine the Quad Mesh and capture further details and reduce the amount of rounding near sharp edges.


5. Convert to CAD: Convert the refined (or un-refined), quad mesh, into a CAD Body using the CAD Body from Mesh block (This block has been renamed to CAD Body from Quad Mesh in 3.17).



6. Export: Add an Export Part block and choose your save location and file type, either STEP or Parasolid. If you are exporting to Solidworks or Siemens NX, we recommend using the Parasolid format so that no translations are needed. 

Once your part is exported, you have the freedom to import it into any program that accepts STEP or Parasolid inputs. The part can have further operations applied to it, be added back to a larger assembly, and more. 

And that’s it! You’ve successfully exported your part in a CAD format

Are you still having issues? Contact the support team, and we’ll be happy to help!

Download the Example file:

More on this topic:


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