OOF2: The Manual

Find the element edges (Segments) that need to be refined. These are specified by the targets parameter, whose value is a RefinementTarget object. Different kinds of RefinementTarget objects pick segments in different ways, for example, by choosing all edges of heterogeneous elements or the long edges of skinny elements. See RefinementTarget for the details.

Figure 6.96 (a) shows a Skeleton that needs to have its heterogeneous elements refined. Setting targets to CheckHomogeneity marks the edges of all elements whose homogeneity is less than 90%, as shown in Figure 6.96 (b).

The divider parameter determines how and where the chosen segments will be divided. Segments are marked for division in in half (Bisection), in thirds (Trisection), or at TransitionPoints.

After the segments are marked for division, each element is replaced by a suitable collection of smaller elements, such that each marked segment of the old Skeleton turns into a set number of segments of the new Skeleton. Exactly how this is done depends on the setting of the rules parameter. (For details, see the description of RuleSet.) The rules sometimes allow more than one way of subdividing an element. In those cases, the total effective energy of the new elements is computed, and the configuration with the lowest energy is used. The parameter alpha determines the relative contributions of shape and homogeneity to the effective energy, as discussed in Section 2.4.2.2.

Figure 6.96 shows the result of refining a mesh using divider=Bisection with alpha=0.3.