rescaling an object in world coordinates

sriesch

I think I am misunderstanding how rescaling of an object works when the Tool Settings pane's dropdown is set to "Use World Coordinates". Can somebody clarify what this option means, and/or how to actually resize an object in the world coordinates along one axis only?

See screenshot. I have a cube.

If I leave it in the default position and drag the "Scale in Y" handle of the universal tool upwards along the world's Y axis, it stretches along that axis as expected. If I rotate the cube 45 degrees along the X axis, then try again, instead of stretching along only the Y axis, it stretches along BOTH the world's Y axis AND the world's Z axis.
What I want to do, in addition to understanding what's going on, is to stretch it only along the world's Y axis (see embedded Bryce screenshot to the right showing what I incorrectly thought was going to happen.)

Richard Haseltine

You can't do that directly. You could with a DForm, if you stretched the field and adjusted the fall off so that it was uniform across the object, or you could export the rotated cube as OBJ and then reimport it, to freeze the rotation so that the y axis now went across the diagonal.

sriesch

Ok. What is this option actually doing then, if not rescaling along a world axis?

Richard Haseltine

The axis options are, a far as I know, for rotation and translate - rotation makes it easier to avoid gimbal lock, and translation makes it easier to line things up (though I want the ability to set the axes to those of an object's parent, that would really help with placing an item in a hand for example).