Think about how often you have to pan and zoom in a drawing in AutoCAD. If you zoom inside a viewport whose scale you’ve set, then — kaboom! — you’ve just blown the scale problem off the map. Luckily, you can prevent yourself, or anyone else, from inadvertently destroying the beautifully arranged and scaled viewport. Follow these steps to set up the viewport:

  1. Verify that you’re in paper space. (Check the UCS icon or move the crosshairs.)

  2. Select the boundary of the viewport whose arrangement you want to protect.

    When the viewport is selected, the Viewport Scale button reappears with its selectable list of scales; and beside it, another button sports a yellow, unlocked padlock icon. As its tooltip indicates, its function is to lock and unlock viewports.

  3. Click the Lock/Unlock Viewport button to lock the viewport scale.

    The yellow unlocked padlock changes to a blue locked padlock, and the Viewport Scale button becomes unselectable. Locking the display makes for some nifty zooming. If you’re in paper space, a normal zoom is executed. If you’re in model space inside a viewport, a normal zoom would wreck the scale, so when you zoom, AutoCAD nearly instantaneously switches to paper space, zooms you in, and switches back to model space.

    As the drawing progresses, you may find that you need to modify viewports and what is shown in them. No problem: Viewports are simply AutoCAD drawing objects, so they can be manipulated accordingly.

    In particular, you can use grip-editing to move and resize viewports. You may also need to pan model space to display items correctly. Again, it’s no problem: Simply unlock the viewport, double-click to enter model space through it, and pan. Double-click outside the viewport to exit model space.

If you blow the scale on the viewport, simply reset the viewport scale again and lock it again.