Modifying the Element Size Using Refine and Adapt
All meshes can be modified using the Refine and Adapt operations. The Refine operation splits elements a specified number of times by inserting new mesh vertices and mesh edges in the existing elements (see the upper right image in Figure 8-15). For a larger mesh, it is often quicker to refine an existing mesh instead of remeshing with finer mesh size settings. The Adapt operation is more general and can both refine and coarsen meshes based on a solution’s error estimate, an absolute size, or an isotropic metric (see the lower right image in Figure 8-15). The operation is free to move mesh vertices and also remove mesh vertices. The Adapt operation can also be used to improve the quality of an imported surface mesh, as discussed in the section Remeshing Imported Meshes.
Figure 8-15: Comparison of meshes modified by Refine and Adapt. The Refine operation refines all mesh elements, also the smaller ones at the top of the sphere. The Adapt operation coarsen the mesh at the top and refines the larger elements, resulting in more uniform mesh sizes.
Both operations place new and moved mesh vertices on a higher order representation of the faces and edges. This means that a refined mesh will resolve curved faces better. See Figure 8-15 where the spherical shape is better resolved in the images to the right.
For more information about modifying a mesh based on an error estimate, see the section Meshes Generated by Adaptation.