ISO/TS 10303-1706:2018-11 specifies the application module for
Non feature shape element.

The following are within the scope of
ISO/TS 10303-1706:2018-11:

• identification of an auxiliary shape information in the product model. For example annotation information;
• identification of an auxiliary shape that defines meta information for physical shape;
• identification of an auxiliary shape that defines graphic registration marks;
• identification of the relationship between an auxiliary shape and the physical shape model it supports;
• identification of a portion of an auxiliary shape without it's purpose definition;
• identification of a portion of an auxiliary shape used to visually indicate a reference alignment for tooling purposes;
• identification of a portion of an auxiliary shape used specifically for the purpose of providing a description of an interface
  plane;
• relationship between two auxiliary shapes;
• relationship between two portions of an auxiliary shape.