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 Creating 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 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.
Design layer viewports replace the layer link functionality present in the Vectorworks Fundamentals product. Current layer links can be easily converted to a design layer viewport with the Modify > Convert > Convert to Viewport command (Vectorworks Design Series required). (See Converting Layer Links.)
The search criteria used in worksheets and in the Script Editor allow you to filter out items from design layer viewports, to prevent unwanted duplicates in schedules.