Cardinal Splines

As far as I know, there is no nice built-in function for drawing cardinal splines with DirectX. You'll have to write your own.

This site has information on interpolating different types of curves, and should help you should you chose to write your own functions.

But are you after this because you need to draw a cardinal spline? Or do you just want curves? What'cha doing?

Thanks that looks good and was what I was after, basically I was looking for a fairly easy way to create a curved 3D camera path and my mathy friend just said I should use cardinal splines, do you think that they are the best ones to use?
Also I would like to find a directx implementation to have a look at to find the best way to approach the prob...

Thanks very much

I would think just using the built in spline functionalty (to D3DX) would be simpler. Plus maybe throw in some quaternions for smooth rotations, etc.

Thanks, in the end I settled on this, which seems to work:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/directx9_m/directx/ref/ns/microsoft.directx/c/unsafenativemethods.vector3/m/hermite.asp
Thanks