To get a smoothed out evenly distributed shape, filleting is usually the right tool for that job.

So for your example here, start with the object like this with sharp corners (3DM model attached):



Select these edges here:



And then run the Construct > Fillet command, that will build some smooth rounded edges for you with absolutely no pinching or worrying about how to build cross sections or anything like that:




However, if you want to try to build something without using the best tools for the job with one hand tied behind your back while trying to pound a square peg into a round hole, I can't really help you with that other than to give you this advice: Don't do that.

- Michael