Can I mask certain edges/vertices/faces from a subdivision surface modifier? I am working with small models and want to have some edges sharp yet others smoothed. Because of how think the object is and how I beveled it, it looks horrible when smoothed. I'd like it if I could somehow mask certain edges or faces from it, or to choose faces that should be sharper?
I have tried to add loop cuts and bevels, but with how badly I made the model, it wont work with the vertices. I will try moving them and seeing if they may be overlapping, or I messed up by making a complicated panel without extra edges. But loop cutting isn't working as it should.
I also tried adding creases but they didn't change anything about how the model looks with the modifier. I will show images of all that I tried. I want to have the sides sharp, but the inside smoothed out. I don't know if shade smooth renders, but it it does it still looks weird for what I am going for.
I also tried using an edge split modifier, but it didn't change anything either, like the previous answers. I did clean up the vertices, there aren't doubles. 
