When you create a drawing view, the program automatically creates a viewport around it. It looks like a border, and it can any shape or size. viewport borders created automatically for base, ortho, iso, multiple, and auxiliary views fit parametrically around the part. However, you can turn parametric sizing Off to size a viewport border manually.
By default, viewport borders are not visible. To redefine viewport borders, make them visible first.
The size of the part or geometry controls viewport borders for base, ortho, iso, multiple, and auxiliary views parametrically, but not borders for detail views. You can redefine the viewport boundary for detail views.
As with viewport borders for detail views, you can create a custom boundary for broken views. However, unlike detail views, you cannot modify viewport borders for broken views by grip editing the viewport borders. Doing so provides unpredictable results.