As mentioned earlier, there are several advantages to drawing objects in 3D, including viewing the model at any angle, automatic generation of standard and auxiliary 2D views, rendering and hidden-line removal, interference checking, and engineering analysis.

AutoCAD supports three types of 3D modeling: wireframe, (which is covered at the beginning of the chapter), surface, and solids.

The surface model is more sophisticated than the wireframe model. It defines not only the edges of a 3D object but also its surfaces. The AutoCAD surface modeler defines faceted surfaces by using a polygonal mesh. It is possible to create a mesh on a flat or curved surface by locating the boundaries or edges of the surface.

Solid modeling is the easiest type of 3D modeling. Solids are the unambiguous and informationally complete representation of the shape of a physical object. Fundamentally, solid modeling differs from wireframe or surface modeling in two ways:

• The information is more complete in the solid model.

• The method of construction of the model itself is inherently straightforward.

In wireframe or surface modeling, objects are created by positioning lines or surfaces in 3D space. In solid modeling, you build the model as you would with building blocks; from beginning to end, you think, draw, and communicate in 3D. One of the main benefits of solid modeling is its ability to be analyzed. You can calculate the mass properties of a solid object, such as its mass, center of...