The extensible ENUMERATION type datum_reference_modifier_type is used when there is a value provided for the node in the tree structure and provides an assertion that the shape of the associated feature used to establish a datum is circular, cylindrical, spherical, two parallel planes, or a projected length as defined in ISO 5459.

Dimensional tolerances

ISO 10303-47 provides dimensional_size to represent dimension of one feature and dimensional_location to represent dimension between two features. The standard also provided a mechanism to qualify the value assigned to the dimension.  To support the new requirements additional mechanisms have been provided, keeping in mind the requirement for upward compatibility.
There are three mechanisms that may be used to qualify the values assigned to the dimensional_size. The shape_dimension_representation.name associated with the dimensional_size may be assigned a value to specify a local override of the tolerance principle applied to the design model. The Application Object Geometric_dimension in ISO/TS 10303-1050 specifies a local override status of the default tolerance principle with the ‘tolerance_principle’ attribute. For qualifying the value of the dimension (e.g., maximum), the value may be represented with a qualified_ representation_ item. For cases where modifiers common to geometric tolerances are applied (e.g., statistical_tolerance, continuous) a geometric_tolerance_with_modifiers may be applied.
ISO/TS 10303-1050 Dimension tolerance supports assigning radius and diameter values to features or elements of features appropriate for the following underlying geometric models: circular, cylindrical, spherical and toroidal. For a toroid, a complete enumeration of the possible radii and diameters is included.
Examples
An example is the “all over” symbol. The user interacted with the authoring system to place the symbol and associated elements of the symbology in an annotation plane. The user associates the elements to a point on the surface of the geometric model. The authoring system will generate the requisite instances of product_definition_shape and geometric_tolerance (referencing that product_definition_shape) so that the receiving system can programmatically determine that the geometric_tolerance applies to the entire product surface. The “all over” symbol itself is not exchanged.

Geometric tolerances

Geometric tolerances are used in the specification of a feature of the surface of a product. A geometric tolerance defines a tolerance zone, which is a region in space in which the product feature must lie. The shape of the zone depends upon the kind of tolerance and feature. When necessary, the location and orientation of the tolerance zone is specified with respect to a datum system. Improved support for tolerance zone requirements indicated in the updated ASME and ISO standards is included in the second edition of ISO 10303-47 but tolerance zone is not discussed further in this document. The ASME term feature control frame and the ISO term tolerance frame are represented in ISO 10303-47 by the geometric_tolerance ENTITY type, its subtypes and related entities. Extensive work has been done to update the geometric_tolerance ENTITY type to meet the updated ASME and ISO standards while ensuring that existing assets are minimally impacted. Domain specific subtypes of geometric_tolerance include: