main parts of a 3d viewer

what are the main parts of a 3d viewer and how could i implement this using the open gl;thank u.

You learn how to program first.

Don’t take this the wrong way, but asking this question indicates to me that you might not be ready for a project like this. To see what other viewers are like, just look at some. For a viewer, you’ll probably be doing a lot of OS specific stuff like mouse events, menu events, etc. For that stuff you’ll have to know how to program for your OS pretty well and should learn that first. There’s also the option of using Glut, but that isn’t as nice for being able to create things like menus.