Tipster Michael Viscetto explains how to create viewports from objects in AutoCAD.
"I ran across this method as I was looking for a way to create a viewport in the shape of a circle. I am a bit old-school, so I typed MV at the Command prompt, and lo and behold I saw the Object option. I pressed the F1 key and found that I can select a circle to convert that shape into a viewport. From the ribbon, you can get there by going to the Layout tab, and from the Layout Viewports pull-down menu you can select the Object option.
"The following is from the AutoCAD Help menu:
Object: Specifies a closed polyline, ellipse, spline, region, or circle to be converted into a layout viewport. If you select a polyline, it must be closed and contain at least three vertices. It can contain arc segments as well as line segments."
Notes from Cadalyst tip reviewer Brian Benton: There are several ways to create a viewport in AutoCAD's paper space; MView is one of them. There are many options available in the MView command. The Object option allows users to create a viewport based on a closed shape (a circle, a region, a closed polyline, etc.). This is nice because you can "clip out" parts of your linework that you don't want to show in paper space. If you already have a viewport made, you can "clip" it. Use the VPClip command, select the viewport to clip, then either draw a new polygon shape to create the new view or select an object. (Obviously the object has to be drawn ahead of time, but you get the idea.) This way you can make changes to the edge of the viewport without having to make a new viewport. This is handy if you have already used some viewport overrides to layers or have frozen layers in a viewport and you don’t want to have to recreate them.