OOF2: The Manual

Details

Description

EdgeFromNodes is a BoundaryConstructor, used as the constructor argument of the OOF.Skeleton.Boundary.Construct command when building Skeleton boundaries. It creates Edge Boundaries from the currently selected Skeleton Nodes or from a group of Nodes. The Nodes are specified by the group parameter, which must be either the name of a Node group or the special placeholder object, selection.

Edge boundaries must be constructed from a single contiguous non-branching set of Segments. Not all sets of Nodes uniquely define a set of Segments. If more than one set of Segments can be constructed from set of Nodes, OOF2 chooses the set that encloses the most Elements. See Figure 6.73 for examples.

Edge boundaries must be directed. Boundary conditions use the direction to determine the boundary normal and the direction of applied Fields and Fluxes. The direction parameter specifies the direction of the boundary being created. The legal values for direction depend on the topology of the boundary being constructed. When the Segments form a closed loop, the legal values are 'Clockwise' and 'CounterClockwise'. When the Segments form an open line or curve, the values are 'Left to right', 'Right to left', 'Top to bottom', and 'Bottom to top'. OOF2 compares the positions of only the first and last Nodes when determining the direction of an open boundary.

Figure 6.73. Constructing an Edge Boundary from Nodes

Selected Nodes (large blue dots) in a Skeleton.

A counterclockwise boundary constructed from the selected Nodes, using OOF.Skeleton.Boundary.Construct(skeleton='micro:skeleton', name='boundary<3>', constructor=EdgeFromNodes(group=selection,direction='Counterclockwise')). The Nodes formed a well defined boundary.

Adding a single Node to the selection makes it impossible to define a set of Segments. No boundary can be constructed.

Adding yet another Node to the selection makes it possible to define a boundary again.

This set of Nodes defines a single open set of Segments. A boundary can be constructed with OOF.Skeleton.Boundary.Construct(skeleton='micro:skeleton', name='boundary<8>', constructor=EdgeFromNodes(group=selection,direction='Left to right')).