Some of the most useful new features in AutoCAD 2012 are those that didn't make the headlines. Blend Curves is one such tool that slipped under the radar but it solves a problem that is very difficult to resolve manually. Curiously, this little gem is hidden under the Fillet tool on the Modify panel, so even if you're already using AutoCAD 2012, it's possible that you've missed it.
Essentially, Blend Curves creates a spline that is tangential to any 2 existing curves (Arcs, Splines or Polyline arc segments).
How to join 2 arcs with Blend Curves
Draw two arcs similar to the ones shown below.
On the Home tab of the Ribbon, click the Fillet flyout in the Modify panel and select Blend Curves.
Follow the prompt and select the two ends of the arcs that you want to join. The result should be similar to the illustration below.
The default setting for the spline gives a good result but if you need to tweak the form of the spline, just pick it to select it and edit the spline by stretching the vertices until you have it just the way you want it.
Blend Curves is a great productivity tool that you may only use occasionally but it's so efficient at what it does that it's worthy of its place on the Modify panel.
