Dynamic Block Stretch Problem

[Anonymous]

I am trying to create a dynamic block of a curtainwall frame that I can place onto a 3D skeleton building elevation.  The frames will vary in height, and the vertical members will be skewed at various angles (see attached files).  Basically I want to place the block onto the elevation and snap the four corners to points on the skeleton.  I also need to move the intermediate member up and down.

The problem that I am having when I test the block is that depending on how I stretch the frame the grips will move away from the frame corners as it becomes a parallelogram.

How can I stretch it and keep the grips at the corners?

Thanks in advance.

Frame BlockElevation

[S.Faris]

I've tried to get this done and 2 troublemakers when put together in this case are (1)Intermediate Member (2)Constraints. I would suggest to make 2 different blocks.

1. Outer Frame
2. Intermediate Member

[Anonymous]

Thanks for looking at it Salmanul.  Two blocks isn't really an option for me.  I think when I get back to work Monday I am going to modify it by adding two angle parameters in the lower corners with a list of angles and see how that goes.