Export True .STEP/STP
What is the difference between the two reconstruction modes?
Automatic attempts supported CAD feature recovery, then surface reconstruction, and finally an original-face fallback. Preserve original faces directly converts each valid source polygon into a CAD face after degenerate geometry cleanup. Choose Automatic to attempt bevel recovery, or Preserve original faces to retain the source face boundaries.
Will every bevel become a real CAD fillet?
Bevel recovery depends on the geometry. Recognized circular rounds can become analytic CAD surfaces; supported non-circular bevels can become fitted CAD surfaces. Unsupported structures may use the original-face fallback. Preserve original faces does not rebuild fillets. Check the final Info message to see which result was produced.