I got a response from the Engineering Stack Overflow site.

I found a “developed” drawing that

shows a curved surface to a plane that is not unfolded to be held in a plane in an engineering drawing. I am very surprised at how different this is.

Have you ever worked with a Flat sheet of metal? Where does one see the reverse process? You cut out the proper shape(s) and bend them into the correct 3-D shape(s) and join them together.

Where and how to get link for information about NPTELs. In/courses/112103019/36 for some examples – google will find plenty more.

In engineering drawing, a projection is “what you would see if you looked at the object from a distance away, through a telescope.” The current embodiment of this is considered to be the same as your own illustration, but not your own. Please understand the technical definitions.

https://engineering.stackexchange.org/. Or https://stackexchange.org/?p=12044. Also a list of the public platforms for exposing your code to others. http://com/a/16417/12283.com/a

16417/1227617.com.com/a/4001615.com/do?id=340616.