Summary

Commands operate in either model space or paper space. You use model space (the Model tab) to do drafting and design work and to create two-dimensional drawings or three-dimensional models. You use paper space (a layout tab) to create a finished layout of a drawing for plotting.

When you are in a layout, you can enter mspace at the Command prompt to make the last viewport in the layout current, and then work in model space in that viewport within the layout. You can switch to model space by double-clicking a viewport, and you can switch to paper space by double-clicking an area of paper space.