A sheet layer viewport displays a full or cropped view of one or more design layers, which you can change as needed and not affect the original drawing. For example, change the viewport’s layer and class visibilities, use a different render mode, or add annotations and dimensions. (See
Presenting Drawings with Sheet Layer Viewports.)
Design layer viewports provide different functionality, for more flexibility. Like a sheet layer viewport, a design layer viewport can display design layers from the current file in a full or cropped view; unlike a sheet layer viewport, it can include one or more design layers that are workgroup referenced from another file.
Like a sheet layer viewport, in a design layer viewport you can control layer and class visibility, and create layer and class overrides. However, because it is an object on a design layer, a design layer viewport has the same view, scale, and render mode as everything else on the layer. You can use 2D and 3D drawing tools to add objects to the design layer, but you cannot add annotations to a design layer viewport.
The Organization dialog box differentiates among the various types of viewports in the Viewports tab. In the following example, the Type column indicates that Viewport-1 and Viewport-2 are design layer viewports, while Viewport-3 is a sheet layer viewport. The Source column indicates that Viewport-1 contains design layers from an external file, while Viewport-2 contains internal design layers.