I hope the title didnt confuse you its a bit hard to explain since im new and dont know everything yet.
So let me explain in a bit more detail. Im trying to make a lipton ice tea glass in blender.
I started with placing a cylinder and made it into the bowl/top of the glass(check the pics for a more clear understanding). I deleted the top face so its a open cup. I then added a solidify and a subdivision surface but didnt apply them yet.
Now here is where it went wrong i extruded the bottom of that glass to make the trunk/beam (which goes to the feet). But the top and bottom of that beam are open. When i select all vertices on that line and fill it in by hitting F it makes a plane but it isnt connected to the glass because of the subdivision surface.
Im sorry i find it a bit difficult to explain hopefully my pictures are understandable. At the end all i want is to close the hole in the bottom of my glass so it wont spill fluid.
Here you see the hole from the top
Here you see the vertices i filled in by pressing F. As you can see it doesnt make any contact to the actual glas. This is the topview/inside the glass