Some Important Rules Governing Cut Sections that Must be Clearly Understood

Some important rules governing cut sections that must be clearly understood:

• Cut planes can be defined in up to three directions potentially with multiple parallel planes. Planes may be stored on disk and retrieved at will.
  
  
• The plane(s) will only be active when the cutting switch is on and the checkbox for the corresponding direction D1, D2 or D3 is selected. The cutting switch can be used to turn off all cut planes and to turn them back on later. The switches for D1 etc. turn off or back on the plane in the corresponding direction, possibly together with parallel cuts. By default only direction D1 is selected, but the main cutting switch is off, so a single plane appears as soon as the cutting switch is turned on.
  
  
• Only Solid, Shell, Beam and Thick shell elements are cut. Other element types, such as joints, springs, stonewalls, etc, are unaffected. You may want to remove these from the display when using cut planes since they will span the plane.
  
  
• Forces and moments on cut planes are also only calculated for elements of these four types which are unblanked, the others are ignored. This is because these are the only element types for which stress &/or force results are consistently available.
  
  
• Forces and moments are calculated from solid and thick shell stresses, shell force and moment resultants, and beam forces/moments. Therefore if any of these are rigid no forces will be computed for the relevant materials, even though the elements may be carrying load.
  
  
• Forces on planes are calculated reasonably accurately. Moments are only approximate and should only be treated as (usually under-) estimates.