Excluded Surfaces, Excluded Edges, and Excluded Points
Some constraint nodes, especially for structural modeling, include (depending on the space dimension and the geometry level of the constraint node) Excluded Surfaces, Excluded Edges, and Excluded Points sections, which are only available when Advanced Physics Options is selected in the Show More Options dialog box. You can use the settings in these sections to exclude some lower-level entities form being constrained for a certain boundary condition or constraint on the domain level. Conflicting Dirichlet conditions, such as constraints, can cause problems for several reasons:
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If constitutive properties differ a lot between two adjacent domains, the flux will be sensitive to whether a Dirichlet condition on a boundary includes the common edge or not.
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When you want to mix weak and pointwise constraints on the same degree of freedom, they cannot coexist on nodes shared at, for example, a corner.
The Excluded Surfaces, Excluded Edges, and Excluded Points sections contain settings for selecting surfaces (that is, boundaries in 3D), edges (that is, boundaries in 2D and edges in 3D), and points, respectively. See About Selecting Geometric Entities for information about selecting geometric entities such as edges.