Engineering technician Hayden Clarke sent in a tip recommending a command added to AutoCAD in a recent release.
"I want to let readers know about the new command Blend, which was introduced in AutoCAD 2012. This command is used to create an editable spline of best fit in the gap between two objects, using the endpoints of the selected lines or curves. Blend has obvious uses for such tasks as contour development — it is a great new feature."
Notes from Cadalyst Tip Reviewer Brian Benton: To use this command, type Blend on the Command line and choose your first object near the endpoint you want the spline to connect to. Pick the second object, near the endpoint you want the spline to connect to. When you start the command, before you select the first object, there is a Command line prompt. Type Con (for Continuity) and choose between two types of blends: tangent or smooth. Tangent blends create a degree 3 spline with tangency to the selected objects at their ends. A smooth blend creates a degree 5 spline curvature with continuity also at the selected objects endpoints. A smooth blend uses control vertices that you can grip-edit, whereas the Tangent blend uses fit points — otherwise the spline is the same.