Hi jetblast, yes like Pilou says Twist can work in any direction and the direction it uses is determined by the start and end axis points that you pick in the first stages of the command.

If you're getting a twist in the z axis it should only be because those 2 points are oriented along the z axis direction...

If you're still having problems with it could you maybe post the 3DM model file with the thing in it that you're trying to twist?

- Michael