Set Model Space Viewports

You can split the drawing area into one or more adjacent rectangular views, which are also called model space viewports on the Model tab.

For example, If you choose 2 or 3 viewports, you can set the arrangement of viewports: Three viewports: [Horizontal/Vertical/Above/Below/Left/Right]<Right>:

You can easily split and join the model space viewports. If you want to join two viewports, they must share a common edge of the same length.