22 AutoCAD and Its Applications—Advanced Copyright Goodheart-Willcox Co., Inc. Constructing Solid Primitives Constructing Solid Primitives As you learned in Chapter 1, a primitive is a basic building block. The eight solid primitives in AutoCAD are a box, cone, cylinder, polysolid, pyramid, sphere, torus, and wedge. These primitives can also be used as building blocks for complex solid models. This section provides detailed information on drawing all of the solid primi- tives. All of the 3D modeling primitive commands can be accessed using one of several methods. You can use the Primitive panel in the Solid tab of the ribbon or the Modeling panel in the Home tab of the ribbon. You can also type the name of the solid primitive. Using the Modeling panel in the Home tab of the ribbon is shown in Figure 2-1. The information required to construct a solid primitive depends on the type of primitive being drawn. For example, to draw a solid cylinder, you must provide a center point for the base, a radius or diameter of the base, and the height of the cylinder. A variety of command options are available when creating primitives, but each primi- tive is constructed using just a few basic dimensions. These are shown in Figure 2-2. Certain familiar editing commands can be used on solid primitives. For example, you can fi llet or chamfer the edges of a solid primitive. In addition, there are other editing commands that are specifi cally for use on solids. You can also perform Boolean operations on solids. These operations allow you to add one solid to another, subtract one solid from another, or create a new solid based on how two solids overlap. PROFESSIONAL TIP PROFESSIONAL TIP Solid objects of a more free-form nature can be created by fi rst constructing a mesh primitive, editing it, and then converting it to a solid. This process is covered in detail in Chapter 9. Using Dynamic Input and Dynamic Feedback Dynamic input allows you to construct models in a “heads up” fashion with minimal eye movement around the screen. When a command is initiated, the command prompts are then displayed in the dynamic input area, which is at the lower-right corner of the crosshairs. As the pointer is moved, the dynamic input area follows it. The dynamic input area displays values of the cursor location, dimensions, command Figure 2-1. The Modeling panel in the Home tab of the ribbon. Pick Solid primitives Pick to create a polysolid