Specification shall bed determined a posteriori
Self-intersection, topology_related_to_self_intersecting_geometry, self_intersecting_geometry, Always erroneous in any application, Informal rule in Part 42
Small segment/patch, nearly degenerate segment or patch or boundary, indistinct curve/surface knots, nearly_degenerate_surface_boundary, short_length_curve_segment, small_area_surface_patch, narrow_surface_patch, nearly_degenerate_surface_patch, extreme_patch_width_variation, Maybe problematic for some systems, e.g. projecting curve onto the surface. Relatively narrow patch.
Bad condition of curve/surface normal, Normal value, zero_surface_normal, Always problematic when the zero normal location is evaluated. But some systems always create this for vertex region of fillet., surface_with_small_curvature_radius, curve_with_small_curvature_radius, Basically bad shape, but it's difficult to set threshold, Because it is not logically linked to system point coincident tolerance. -> That decreases severity of these criteria., Change of direction, steep_geometry_ transition_across_edge, steep_angle_between_adjacent_edges, steep_angle_between_adjacent_faces, abrupt_change_of_ surface_normal, Maybe problematic for some systems, e.g. projecting curve onto the surface
Specification can be explicitly determined from various conditions
occurrence possibility is low
Severity is extremely high when occurred.
It's very rare to use these for data from stable systems
Some criteria are used for cleaning up very dirty data. In this case, experiment is needed to specify criteria to be used.
Restriction of mathematical representation, inapt_topology, excessively_high_degree_curve/surface, discontinuous_geometry, These criteria are to be automatically handled by data translator if possible, or checked just before translation.
Basic accuracy of CAD, nearly_degenerate_geometry, geometric_gap_in_topology, small_volume_solid and entirely_narrow_solid, Severity is high when occurred, Why not included in CAD specification dependent? -> criteria in "CAD specification dependent" arena is the ones to be handled in general data translator. And many CAD don't use fixed value., It is not easy, and sometimes undesirable to handle these criteria in data translator