Seeds are markers that you place along the edges of a region to specify the target mesh density in that region. Both the mesh density along the boundary of the region and the mesh density in the interior of the region are determined by the seeds along the edges of the region.

You can create and control seeds using the Seed menu in the Mesh module main menu bar. ABAQUS/CAE generates meshes that match your seeds as closely as possible. You can distribute seeds uniformly along an edge, or you can bias their distribution toward one end of the edge, as shown in Figure 17–6.

Only minimal seeding is necessary if you do not have strict mesh requirements. For example, you can seed just one edge of the part instance or region and then let ABAQUS/CAE use a similar element density for the unseeded edges.

If you want more control over the mesh, you can partition the region and then provide seeds along the partitions you have created. This technique is described in greater detail in “Verifying and improving meshes,” Section 17.6.

Mesh seeds specify only a target mesh density. If you are using hexahedral or quadrilateral elements, ABAQUS/CAE often changes the element distribution so that the mesh can be generated successfully. You can prevent such adjustments by constraining the number of seeds along an edge. When you constrain seeds, you are prescribing mainly the number of elements along the edge, and, to a lesser extent, the precise locations of the nodes; if necessary, ABAQUS/CAE adjusts the locations of the nodes to reduce element distortion. In addition, you should use such constraints with care, since they can make it more difficult for the mesh generator to obtain a mesh.