One note about moving the center and end points. The term "Center Point" may be a bit counterintuitive in a sense. I think "Pivot Point" would probably describe it more accurately. 

For example, the door of the car. The "Center Point" would actually need to be at the front end of the door where it hinges to the car body while the "End Point" would be at the opposite end of the door that swings wide.

Just keep in mind that the Center Point is the center of rotation for that object or part.

Hey! His nose is dry! ... Someone should lick it,  just in case. - Diego