Remove the limits in z of all cylinders.
ON_OFF : 1 -> remove limits 2 -> restore limits.
From /ZTBAR/ NCYL, total number of cylinders From /ZTFWD/ NPLA, total number of planes. if ON_OFF = 2 : From FBUFS and BBUFS : copy of real geometry.
To /ZTBAR/ ZMN and ZMX, z limits of Z cylinders. To /ZTFWD/ ZED , z positions of planes. if ON_OFF = 1 : To FBUFS and BBUFS : copy of real geometry.