To load additional geometry into a partially open drawing
The Partial Load option is available only if the current drawing is a partially open drawing.
The default view is Extents. You can load only geometry from model space views that are saved in the current drawing.
If you do not select a layer or layers to load, no layer geometry is loaded into the drawing, but all drawing layers exist in the drawing. If no layer geometry is specified to load into the drawing, no geometry is loaded even if the geometry from a view is specified to load. If you draw objects on a layer that is not loaded, you may be drawing on top of existing geometry that is not loaded in the drawing. You cannot unload any geometry that is loaded in the current drawing.