Hi İ recently started working with Comsol and have a few basic queries. İ am using Comsol version 5. 1. İ am trying to use parametric sweep. So i used it once and saved the file. Now when i try to change the range of sweep it is giving me an error : "parameter list gives empty sweep". When i enter the old range, it starts running fine. 2. İ was trying to use difference operation. İ had created a sphere and placed a box inside it. The problem is once inside the sphere i am not able to select the box, only sphere is highlighted. Why is that?