Object's Normal Fix, formerly known as Shape Normal Fix, is a small script package for 3ds Max that corrects the normal, or extrude direction, of selected shapes. You select the shapes to fix, run a script, and set the direction from there. For 3D curved shapes, the manual approach is the recommended one.
The script works in three modes. Auto Mode fixes the transform of the object automatically. By Face uses the normal of a picked face, with one left click on a surface to get the normal and a right click to exit. By 4 Points uses the first two points for the X-axis and the third and fourth for the Y-axis, with point order determining axis direction. A Geo Normal Fix script is also included, working like the manual shapes fix but for geometries.
Each mode has its own MacroScript, plus a combined macro (with Shift and Control) that can be used as a toolbar button. The macros become visible and enabled when the selection contains shapes. Installing an update automatically removes older versions, and macros must be added manually to the Quad Menu or toolbar.