NX Planar Plate creation with NonPlanar Mold Face

In Ship Structure Detail Design when creating a Plate sometimes the plate is considered to be planar, i.e. Ship Attribute (part) SA_COMPONENT_FORM = Planar, though the plate actually is non-planar. Expectation is SA_COMPONENT_FORM = NonPlanar.

What is the reason behind this and how to overcome it?

The value, (Planar or NonPlanar), of the the form attribute SA_COMPONENT_FORM, which is set upon creation of a Plate as a part attribute in the plate part, is dependent on a customer default setting. In Ship Design --> Steel Features --> Plate tab, Parameters group, Planar Plate Method: which have standards value Modeling Tolerance (standard modeling tolerance is 0.01) For a plate that have a face length of 2000mm this means that a maximum deviation from flatness of 20mm or less is considered to be Planar.

To get a plate where SA_COMPONENT_FORM = NonPlanar, for a plate with face length 2000mm and deviation from flatness of 1mm you would need to make the two NX customer default changes:

- Planar Plate Method: Planar Deviation to Length Ratio

- Planar Deviation to Length Ratio: 0.000499

Please note: Just changing the customer default as mentioned above will not apply to already existing plates. You need to do the customer default change and then all plates created thereafter will be subject to the new planar plate threshold.