In AC 12 manual, top left of page 161, it mentions that:
"GDL Objects can be programed to display themselves according to the Floor Plan Cut Plane". (For me, I'm thinking simple intelligent lines here, not complicated objects).
It goes on to of course talk about display of objects according to the varies settings in Floor Plan Cut Plane, but does not mention how to, (or where to find info for), "program" object(s) to display according to the Floor Plan Cut Plane.
They say it so cavalier, as if it could just be a line or two adjustment in the code for Floor Plane Cut Plane to pick up on it.
Maybe it works in conjunction with the new MVO RCP switch?
Maybe Jim Murray's intelligent line object?
A few pointers to what the F. G.S. means here, would be great.
I believe that to utilize the Floor Plan Cut Plane in the display of an object, then there needs to be code in the object to take advantage of this. There is a Global Variable (page 227 AC 12 GDL Reference Guide):
GLOB_CUTPLANES_INFO  -
array of 4 length values: 1: cutplane height, 2: cutplane top level, 3: cutplane bottom level, 4: absolute display limit, in the library part’s local coordinate system. See details in AC Set Floor Plan Cutplane dialog.
So the Cut Plane info can be utilized (passed to) by the object, this is similar to how the current scale can be used by the object to alter its display. It is up to the object's author to utilize this, I don't see any automatic use of the Cut Plane by the 2D Display of the object.