XPLOT3D is one of IDL's open source procedures, whose code is in the IDL directory tree's 'lib' subdirectory. Apparently, some error was introduced into it starting in version 6.2 IDL. The nature of the error was something like: The value of an XCOORD_CONV keyword property gets used for interpreting the scale of the Y and Z axis ranges, when, actually those axes ranges should be scaled with the value of the ir own YCOORD_CONV and ZCOORD_CONV keyword properties. I hear that 'xplot3d.pro has been fixed for soon-to-be-released IDL 6.4, and I think I can find the fixed copy of this procedurem However, I wonder whether you have viewed the far more powerful and more modern IDL alternative to XPLOT3D ... IPLOT. IPLOT has all the functionality of XPLOT3D with many times more functional and manipulation options, all in a GUI interface that is just as intuitive as XPLOT3D's. James Jones