hi, Would someone be able to explain to me what Hermite and Catmull-Rom interpolation is - and more importantly how I use it?? I''m writing a tutorial for my site on animation using Tweening and interpolation... I''ve gotten all the linear parts sorted, but I''m a little confused as to how I explain or use these two types of vector manipulation - I know that they''re for curves and such, but what does each value mean? FYI I''m using DirectX 8.0, the SDK documents say nothing, and I''m trying to use the D3DX interfaces (D3DXVec3Hermite( ) etc..) Anyone able to help?? Jack;