Hey. I have a case where I'm setting one sphere's transformation in the Y axis relative to another sphere in my scene (which is placed directly at the origin), using this bbox expression:
bbox(“../meshSphere”, “D_YMAX”)

What's strange though, is that this expression is always returning a negative value. Even if I try to use D_YMIN, it's still negative. Similarly, bbox(“../meshSphere”, “D_YSIZE”) is returning a negative value.
…am I doing something wrong here? :?
I mean, it's no big deal. By multiplying the values by -1, I get the values I was expecting. I just find this to be rather…odd.

You don't want the quotes around D_YMAX. It should be
bbox(“../meshSphere”, D_YMAX)

with the quotes, I think what happens is that “D_YMAX” is undefined, so it resolves to 0, which means it delivers X_MIN, which, since you have a sphere, is coincidentaly the same as Y_MIN.

Ahh. Yeah, that was it. I had tried entering it that way once before, but it wasn't working right. Must have overlooked something that time.
But it's working now. Thanks.