Hi Mike,

> When running the Extrude command on a curve or a
> line (not a surface) it wants to default in the Z direction
> to make a surface from the curve.

Actually it doesn't work like that - if the curve is planar it will extrude along that plane's normal, see the attached file for an example, note that extruding either of these curves does not result in going in the Z direction by default.

If you have a curve that is not planar, it will try to do a best fit plane to it, and then find which of the x, y, z axis directions has the closest angle to that and then use that axis direction. That makes things that are nearly planar but not quite have a reasonable default direction.

If you are only extruding just a single line and nothing else with it, then that's the particular case that will default to z, that's kind of a special case because there is no "best fit" plane to a line segment, there's basically an infinite number of planes that can contain a particular line (with the planes all pivoting around the line at different rotations).

Is it that case of extruding a single line segment the one that is getting you?

- Michael