Graphics Programs Reference
In-Depth Information
your 3D models from any angle, or slice through them to see what they look like inside.
And finally, since the world of technical drawing is still a two-dimensional one, you can
use AutoCAD's viewing options to create 2D views from 3D models.
If you're an AutoCAD LT user, you're going to have to sit out most of this and
the next two chapters. One of the major areas where AutoCAD LT differs from reg-
ular AutoCAD is in its extremely limited 3D functionality. Even viewing 3D models
is much more difficult in AutoCAD LT than it need be. LT users
can
acquire nearly
all the 3D
viewing
capabilities of the full version of AutoCAD, but you need a sep-
arate — and free — program to do so. Just go to
www.autodesk.com/trueview
and
download DWG Trueview.
This chapter takes a look at some of the tools available in AutoCAD 2012's 3D Modeling
workspace and introduces you to many of the general concepts of creating 3D objects.
You also discover how to look at your model from different viewpoints, and how to
change the way it appears on-screen.
3D modeling and visualization is a lot more demanding on computer hard-
ware than 2D drafting is. 3D models tend to be bigger than 2D drawings, so you
may need more disk space. And you'll certainly be happier with more than the
bare minimum of RAM required for 2D in AutoCAD. In Chapter 2, I list AutoCAD
2012's system requirements and point out the increased resources needed for 3D
work.
Understanding 3D Digital Models
There are three basic types of 3D computer model:
Wireframe models:
Consist of edges and vertices only. Although they do occupy
3D space, they're totally unrealistic and difficult to read correctly. AutoCAD
doesn't create wireframe models, although you can view them as such.
Surface models:
Consist of infinitely thin skins that stretch from edge to edge of a
model. AutoCAD can create two different types of surfaces:
Mesh surfaces
, com-
posed of thousands and thousands of 3- or 4-sided faces, and
NURBS surfaces
