PDQ criteria

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PDQ criteria by Mind Map: PDQ criteria

1. Detection of Faulty data

1.1. Bad shape

1.1.1. Self-intersection

1.1.1.1. topology_related_to_self_intersecting_geometry

1.1.1.2. self_intersecting_geometry

1.1.1.3. Always erroneous in any application

1.1.1.4. Informal rule in Part 42

1.1.2. Small segment/patch

1.1.2.1. nearly degenerate segment or patch or boundary

1.1.2.1.1. indistinct curve/surface knots

1.1.2.1.2. nearly_degenerate_surface_boundary

1.1.2.1.3. short_length_curve_segment

1.1.2.1.4. small_area_surface_patch

1.1.2.1.5. narrow_surface_patch

1.1.2.1.6. nearly_degenerate_surface_patch

1.1.2.2. extreme_patch_width_variation

1.1.2.2.1. Maybe problematic for some systems, e.g. projecting curve onto the surface. Relatively narrow patch.

1.1.3. Bad condition of curve/surface normal

1.1.3.1. Normal value

1.1.3.1.1. zero_surface_normal

1.1.3.1.2. surface_with_small_curvature_radius

1.1.3.1.3. curve_with_small_curvature_radius

1.1.3.1.4. 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.

1.1.3.2. Change of direction

1.1.3.2.1. steep_geometry_ transition_across_edge

1.1.3.2.2. abrupt_change_of_ surface_normal

1.2. Redundant data

1.2.1. multiply_defined_*

1.2.2. overlapping_*

1.2.3. overcomplex_*

2. Interpretation of explicit condition

2.1. Violation of mathematical representation

2.1.1. erroneous_data

2.1.2. occurrence possibility is low

2.1.3. Severity is extremely high when occurred.

2.1.4. It's very rare to use these for data from stable systems

2.1.5. Some criteria are used for cleaning up very dirty data. In this case, experiment is needed to specify criteria to be used.

2.2. Specification of CAD

2.2.1. Restriction of mathematical representation

2.2.1.1. inapt_topology

2.2.1.2. excessively_high_degree_curve/surface

2.2.1.3. discontinuous_geometry

2.2.1.4. These criteria are to be automatically handled by data translator if possible, or checked just before translation.

2.2.2. Basic accuracy of CAD

2.2.2.1. nearly_degenerate_geometry

2.2.2.2. geometric_gap_in_topology

2.2.2.3. small_volume_solid and entirely_narrow_solid

2.2.2.4. Severity is high when occurred

2.2.2.5. 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.

2.2.2.6. It is not easy, and sometimes undesirable to handle these criteria in data translator

2.3. Use case

2.3.1. non_smooth_geometry_transition_across_edge

2.3.2. inapt_topology