In ArcGIS 9.3 there is an option to do spline interpolation off spatial analyst. I'm just starting to do interpolation...I've gotten through Kriging and IDW in ArcGIS 10, but I can't find how to do spline (regularized & tension). There are NO tutorials or step-by-step directions anywhere. I really need to do a comparison between surfaces and the two spline examples need to be included... what glaring piece of information am I missing??