The Skip option forces GiD to skip a geometrical entity when meshing (so the entity will not have mesh), while the No Skip option forces GiD not to skip the geometrical entity (so the entity will have mesh) when the 'Skip entities automatically' option is set (see Preferences ). By default, any entity is skipped.
The 'Automatic skip' option lets GiD decide if the geometrical entity should be skipped or not skipped accordingly with the parameters in the preferences window (allow or not to 'join' entities in different layers, and the tangency between entities: those entities that are tangent enough will be skipped when meshing.
Entities with some group, condition or material assigned are never skipped. Entities belonging to different groups are never meshed together.
Using the 'Skip by...' option user can apply some of the useful following criteria to select the entities to be skipped, not to be skipped or to be skipped automatically.
- Tangency limit angle: This criteria select the lines between surfaces in which angles between normals in the surfaces are lower than the value.
- Take care layers: If this is set, lines between surfaces which are in different layers won't be selected.
- Take care curvatures: This ratio means the diference between curvatures in the surfaces that share a line. If the ratio between the curvatures exceeds this value, the shared line is not considered to be selected. As an example, if this value is 0.1 (10%), the only lines which will be selected will be the ones in which the two surfaces that share the line have almost the same curvature (only a 10% of difference is accepted ). As this number increases, probably more lines will be selected.
- Lines of surfaces smaller than: All the lines of surfaces which have some line smaller than this value will be selected.
- By clicking Select by criteria all the selected criteria are used to select the lines.
- Modify selection allows the user to modify manually the selection made.
- When Apply is clicked the marked option (Skip, No skip or Automatic skip) is aplied to the selected lines.