Hi zefreestijl,
Thank you very much for your reply. And the link to Retessellation page is useful. 
It is good tips to know when I want to make minor changes to imported meshes.
As refer to your Datasmith Details screen dump, please refer to my screen dump:
I have changed my data type to “Datasmith CAD…”, there is no options under “Geometry & Tessellation Options”.
I hope to find out if there are any ways that I can specify during or before Dataprep import to set the option to either “Import as NURBS” or “Import Rhino Meshes”. With the Dataprep, I find that I got imported NURBS sometime and Rhino Meshes other time? I do not know why?
From my experiments when testing rhino file imports using Datasmith only. I find:
- the “Import as NURBS” option some objects created weird untrimed meshes. I checked that those objects have no bad surfaces and those meshes are enclosed in Rhino.
- the “Import Rhino Meshes” option gives better meshes but cannot be tessellated as point out in the UE documentation.
I am still learning and trying to find a workable solution to streamline the Rhino file to UE process.
Have a good day. 