Problem with the mesh

Hi everyone,
I have a problem with the mesh being printed. Can you give me some advice? I tried to triangulate the non-planar squares with the mesh function and refine the mesh. Otherwise I tried to convert the mesh to NURBS but the model is quite heavy. Do you have any ideas? Thanks.

You could use Quad Remesh(Mesh–>Triangulation–>Quad Remesh)which is new in R7, and convert the quad mesh output to SubD usingSubD from Mesh(Surface–>SubD–>SubD from Mesh)

Is this to convert the model to NURBS?

Yes, SubD object can be converted to Nurbs using ! _ToNurbs command

The conversion is quite long, as the mesh is complex!

By refining the mesh is it possible to solve the problem and export it to .STL?

And after create a quad-dominant mesh, can I export it to .STEP?

File -->Save As or File–>Export Selected and choose file format in the dropdown…

Thanks.