Hi GoodMorning. 
Thank you for your information. I did not download the UE4.27 at present. I considered myself a new user learning UE. There are much to learn and explore even with the current version UE4.26. Secondly, if problem occurred, I knew it wasn’t an experimental feature. From your suggestion, it is a good improvement in UE4.27. I may install the Preview and try later.
By the way, in UE4.26, there are no other ways to control the Geometry option? From the import experiments with Dataprep that I tried. I found that occasionally it will use meshes generated by Rhino but not always. I just do not know what triggered the option to choose one or the other?