How to draw a spline on a curved surface in Solidworks

There are several reasons to get a sketch curve on a wavy surface.  One of the biggest is to get a swept cut.  The other is to alter feature less geometry.  This would be to trim a curved surface to create a nice blended fillet. 

Insert a 3D sketch and then use Spline on Surface.  When you start to draw on that surface the rest of the spline will follow the curvature of the surface.  

Ketul Patel
Computer Aided Technology, Inc.