What is 3D CAD software? 3D CAD, or 3-dimensional computer-aided design, is technology for design and technical documentation, which replaces manual drafting with an automated process. Used by architects, engineers, and other professionals, 3D CAD provides an extra dimension to precisely visualize and share designs.
A line has two points, a start point and an end point. AutoCAD works with the points to display the line on the screen. Move your cursor over the picture above and you will see line drawn from the absolute points of (-10,-4) to (9,6).. Most of the time you will not have an indication of where the origin is.