Hello Again... I know that R has plenty of functions for drawing splines between two points in 2d, and plenty of ways to fit a spline curve among various points in 2d or 3d (I think), but, is there a function which can be used to draw a simple spline curve between any two points in 3d space? Since such a spline curve would be fundamentally a 2d object, I imagine that if a 3d version exists it would have to have some sort of argument specifying where that 2d plane should be drawn (maybe in cylindrical coordinates?). What I'm looking for would be the 3d analog of grid.curve or xspline. What I'm trying to do is related to the idea of great circles, as implemented in package geosphere, but the curves I'd like to draw are not on the surface of a sphere nor are they parts of a circle. Thanks for any suggestions! Bryan *********** Bryan Hanson Professor of Chemistry & Biochemistry