When you are selecting orphan element faces to create geometry (for more information, see “Create face from element faces,” Section 69.7.10), Abaqus/CAE displays a field in the prompt area. The field allows you to choose between five selection methods—individually, by angle, by limiting angle, by layer, and by analytic, as shown in Figure 6–11.
The angle selection method is described in “Using the angle and feature edge method to select multiple objects,” Section 6.2.3. The limiting angle, layer, and analytic methods are available only while selecting orphan element faces to create new geometric faces.By limiting angle
Selecting objects using a limiting angle is a two-step process:
In the prompt area, you enter an angle (from 0° to 90°).
From the part or assembly, you select an orphan element face.
By layer
Selecting objects using the layer method is a two-step process:
In the prompt area, you enter a number of layers.
From the part or assembly, you select an orphan element face.
Figure 6–13 illustrates the selection of three layers of orphan shell element faces around a starting face and the resulting geometric face.
As shown in Figure 6–13, layer selection can traverse sharp corners and other model features that would normally signify the end of a geometric face. In most cases you should preserve logical model edges and other features by creating separate faces. Otherwise, the resulting geometry may be difficult to repair and mesh.Note: When you are working with solid orphan elements, selections that include multiple faces from the same orphan element are not acceptable for the creation of a single geometric face.
By analytic
The analytic selection method for orphan element faces is based on the recognition of basic shapes in analytic geometry (such as planes, cylinders, cones, spheres, and tori), or portions of these shapes. Analytic selection attempts to recognize the logical boundaries of a set of orphan element faces that would make a recognizable geometric face.
Figure 6–14 illustrates analytic selection of orphan element faces. A spherical section of element faces is highlighted; this selection could not be made using any of the other selection options for multiple objects.
After you use any of the above methods, you can select other methods in the prompt area and [Shift] + Click to append more elements to your selection. You can also [Ctrl] + Click on items to unselect them. In addition, you can continue to use the current method and use [Shift] + Click to append elements to your selection. For more information, see “Combining selection techniques,” Section 6.2.8.
