You can use the following methods to control the seed density along selected edges:

• Specify the average element size for every edge of the entire part or part instance.

• Specify the number of elements desired along an edge.

• Specify the average element size along an edge. (If the edge length is not an integer multiple of the element length, Abaqus/CAE will change the element length slightly to obtain an integer number of elements along the edge.)

• Specify a nonuniform distribution of elements along an edge. The element density can increase from one end of the edge to the other (single bias), or the element density can vary from the center of the edge to each end (double bias). For a nonuniform distribution you can specify either of the following:

  • The number of elements desired along an edge and a bias ratio. The bias ratio is the ratio of the largest element to the smallest element.

  • The size of the smallest element and the size of the largest element.

If you select edges that you previously seeded using a combination of these methods, Abaqus/CAE provides an As Is option that allows you to retain the seeding method. Abaqus/CAE provides a similar option if you select edges with a mixture of curvature controls or seed constraints.

For detailed instructions on prescribing seed density, see the following sections:

• “Defining seed density for an entire part or part instance,” Section 17.16.1

• “Seeding an edge by prescribing the number of elements,” Section 17.16.2

• “Seeding an edge by prescribing element size,” Section 17.16.3

• “Prescribing biased seeding along an edge,” Section 17.16.4

• “Applying constraints to edge seeds,” Section 17.16.5

• “Seeding previously meshed parts, part instances, or regions,” Section 17.16.6

• “Deleting part or instance seeds,” Section 17.16.7

• “Deleting edge seeds,” Section 17.16.8

Seeds created by specifying an average element size for the entire part or part instance are called part seeds or instance seeds, respectively, and appear in white; seeds created using the other methods are called edge seeds and appear in magenta. Edge seeds always override part or instance seeds; therefore, when you specify the average element size for the entire part or part instance, part or instance seeds appear only on edges of the region that do not already have edge seeds. New edges created by partitioning are given part or instance seeds by default.

When you seed an edge of a region that is assigned the swept or revolved mesh technique, the edge seeding tools automatically propagate seeds from the selected edge to the matching edges in the region. In other words, the seeds on the face or edge at the beginning of the sweep path are propagated automatically to the face or edge at the end of the sweep path. Likewise, the seeds created on one edge along the sweep path are propagated automatically to the other edges along the sweep path. As a result, even though you select a single edge of a face to seed, Abaqus/CAE will propagate the seeds to additional edges and faces. For more information, see “What is swept meshing?,” Section 17.9.1.