Meshes and Surfaces - Autodesk AutoCAD 2013 Practical 3D Drafting and Design - page 393

Chapter 12. Meshes and Surfaces
In Chapter 4 , Creating Solids and Surfaces from 2D , we introduced how to create sur-
faces by applying EXTRUDE and other commands to linear objects. This chapter is
about all types of surfaces and meshes.
The topics covered in this chapter are:
• Identifying types of surfaces and their applications
• How to create and edit procedural surfaces
• How to create and edit NURBS surfaces
• How to create and edit meshes
• How to create meshes based on 3D faces
• Analyzing surfaces curvature
Surfaces and meshes are 3D objects with zero thickness. Most of the time, when
modeling in 3D, we apply solids, which give us much better precision; since Version
2010, surfaces and meshes are also available, and can be used for complex and con-
ceptual models. These objects are divided into the following categories:
• Procedural surfaces : These are surfaces created from linear objects,
such as EXTRUDE , REVOLVE , or SWEEP , as we have seen in Chapter 4 ,
Creating Solids and Surfaces from 2D . These surfaces could or could not
maintain association with original linear objects. We will present several
other commands for creating procedural surfaces.
• NURBS surfaces : Non-Uniform Rational B-Splines ( NURBS ) surfaces
are based on splines and are mainly modified by control vertices. This type
of surfaces is mainly applied in the aeronautical, automotive, mould, or any
industry with free-form shapes.
• Meshes : These objects, also called tessellation meshes, are not really
surfaces but allow creating smooth 3D objects.
• Polyface meshes : These are the oldest AutoCAD 3D objects, long before
solids, and are based on 3D faces.