Is there any reason as to why grid_inverse_transform_point(...) is declared twice? -- Andrew Janke ( rotor@cmr.uq.edu.au || www.cmr.uq.edu.au/~rotor ) Australia->University of Queensland->Centre for Magnetic Resonance W: +61 7 3365 4100 || H: +61 7 3800 4042 || M: +61 4 2138 8581