Subdivision Surface modifier deforms mesh on 2.80 I'm learning Blender for a university course, although I already have a few years of experience on 3DS Max. I'm having a problem with the subdivision surface modifier.I have this low poly mesh:



I want to smooth it out, since it only has 8 sides, so I applied the subdivision modifier (it's the only modifier on the mesh and I only increased the subdivision count, I didn't change other options), but I end up with this result:



See how the mesh bends instead of remaining straight? I can't solve that issue. In 3DS Max, a mesh like this, withoud a bottom cap, would have had many more sides added to it (becoming a better cylinder) but the tube sides would have remained straight. I tried: adding various horizontal support loops, maxing out the creasing amount on the bottom edge, closing the mesh and beveling the bottom corner, but I still get that pin cushion effect. Creasing the vertical sides makes the lines straighter but end up with a smoother octagonal shape instead of  a cylinder like I want. What am I missing?
One thing you might be able to do is either make your own bevels, or use the bevel modifier Like so....

I start off with your problem:



After using manual bevels:(after selecting everything, do ctrl+b)



Or you can use the bevel modifier to do it for you:



NOTE: Make sure you decrease the width of the bevel modifier and increase the segments to achieve better results. Experiment with this a bit until you get what you are looking for.

If something like this is happening on a cylinder what you can do is extrude the end inward by pushing e than s, like so:(if not using the bevel modifier)