The first feature you create while building a part is called the base feature; you construct the remainder of the part by adding more features that either modify or add detail to the base feature. This process of building an Abaqus/CAE native part using the tools in the Part module follows a sequence of operations analogous to building a part in a machine shop. For example, you start with a piece of billet stock (the base feature) and then you do the following:
Attach additional pieces to the billet (apply a solid extrusion, a revolved shell, or a sketched wire).
Cut away the billet (apply an extruded cut, a revolved cut, or a circular hole; or round or chamfer an edge).
When you create a new part, you must describe the base feature. You do this by specifying two properties of the base feature: its shape and type. The shape indicates the basic topology of the feature; that is, whether it is a solid, shell, wire, or point. The type indicates which of the following methods will be used to generate the base feature:
Planar
You sketch the feature on a two-dimensional sketch plane.
Extrusion
You sketch the feature profile and then extrude it through a specified distance.
Revolution
You sketch the feature profile and then revolve it by a specified angle about an axis.
Sweep
You sketch two shapes: a sweep path and a sweep profile. The profile is then swept along the path to create the feature.
Coordinates
You enter the coordinates of a single point in the prompt area.
Table 11–1 shows the base features that you can select based on the part's modeling space and type.
Table 11–1 Choosing the base feature.
| Part Type | Modeling Space | |
|---|---|---|
| Three-dimensional | Two-dimensional or Axisymmetric | |
| Deformable | Any | Planar shell, planar wire, or point |
| Discrete rigid | Any (you must convert a 3D solid discrete rigid part to a shell before you instance it) | Planar wire or point |
| Analytical rigid | Extruded or revolved shell | Planar wire |
| Eulerian | Extruded, revolved, or swept solid | Not applicable |
| Fluid | Extruded, revolved, or swept solid | Not applicable |
| Electromagnetic | Extruded, revolved, or swept solid | Planar shell |
A part imported from a file containing third-party format geometry consists of a single feature that you import into Abaqus/CAE as the base feature of a new part. You cannot modify this base feature, but you can add additional features to it. Similarly, a mesh part is created in the Mesh module or imported from an output database as the base feature of a new part. You can use the mesh editing tools to add and delete nodes and elements from a mesh, or you can use the tools in the Part module to add geometric features to the mesh.
