if we import any model it is showing as imported can it will be change in surface or solid
I use pro-e and the models vary a lot and most that have threaded holes will not open as a solid. In pro-e there is a insert data doctor command that usually can repair the model and make it solid.
IN WHICH SOFTWARE DO U WANT TO DO IT?
Edit definition of import feature, idd, repair tangency, green check, green check, and then It should be fixed.