Geometric constraint problem: "The two objects must reside on the same plane."

[alsbergt]

Fellow CADsters,

I have run into a problem with Autocad Architecture 2013, wherein at some point I am no longer able to apply new geometric constraints in a drawing I created earlier.  Commands such as GCPARALLEL on any two objects result in the error message:

The constraint cannot be applied. The two objects must reside in the same plane.

This problem did not occur when working on the same drawing earlier, nor does it occur when I try creating a new drawing.  Something in the state of this drawing must have gone wrong, but I cannot figure out what it is.

There is nothing special I can tell about the objects I try to apply the constraints to in this drawing: the problem happens even with simple walls or plain (already parallel) lines on the XY axis (Z=0).  Even removing an existing constraint (which I had applied before the problem started occuring) and trying to reapply it to the same two objects results in that error message.

I am really confused now, what state in the drawing can affect AutoCAD's idea on whether two objects are or are not on the same plane?

  Any advice appreciated,

  -- Tom

[vinoth_egspec]

Hi, I have this same issue use AutoCAD lisp "ZeroZ" to solve the problem even though your drawings are in Z=0 condition.

[pendean]

@alsbergt FLATTEN command not an option?

In my experience, never rely on just observing that Z=0 in PROPERTIES unless it shows Z=0.00000000 (a units setting): highlight it then actually type 0 then hit <enter> to establish your desire instead.