Book Details :
LanguageEnglish
Pages41
FormatPDF
Size4 MB

# AutoCAD 2016 Tutorial First Level 2D Fundamentals by Randy H. Shih

Learning to use a CAD system is similar to learning a new language. It
is necessary to begin with the basic alphabet and learn how to use it correctly
and effectively through practice. This will require learning some new concepts
and skills as well as learning a different vocabulary. Today, the majority of
the Mechanical CAD systems are capable of creating three-dimensional solid
models. Nonetheless, all CAD systems create designs using basic geometric
entities and many of the constructions used in technical designs are based upon
two-dimensional planar geometry. The method and number of operations that are
required to accomplish the basic planar constructions are different from one
system to another. In order to become effective and efficient in using a CAD
system, we must learn to create geometric entities quickly and accurately.

In
learning to use a CAD system, lines and circles are the first two, and perhaps
the most important two, geometric entities that one should master the skills of
creating and modifying. Straight lines and circles are used in almost all
technical designs. In examining the different types of planar geometric
entities, the importance of lines and circles becomes obvious.

Triangles and
polygons are planar figures bounded by straight lines. Ellipses and splines can
be constructed by connecting arcs with different radii. As one gains some
experience in creating lines and circles, similar procedures can be applied to
create other geometric entities. In this chapter, the different ways of
creating lines and circles in AutoCAD 2016 are examined.

The method we just used to create the freehand sketch is known as the
interactive method, where we use the cursor to specify locations on the screen.
This method is perhaps the fastest way to specify locations on the screen.
However, it is rather difficult to try to create a line of a specific length by
watching the displayed coordinates. It would be helpful to know what one inch
or one meter looks like on the screen while we are creating entities. AutoCAD
2016 provides us with many tools to aid the construction of our designs. For
example, the GRID and SNAP MODE options can be used to get a visual reference
as to the size of objects and learn to restrict the movement of the cursor to a
set increment on the screen.

A CAD file, which is the electronic version of the design, contains data
that describes the entities created in the CAD system. Information such as the
coordinate values in world space for all endpoints, center points, etc. along
with the descriptions of the types of entities are all stored in the file.
Knowing that AutoCAD stores designs by keeping coordinate data helps us
understand the inputs required to create entities.

In AutoCAD 2016, the absolute coordinates and the relative coordinates
can be used in conjunction with the Cartesian and polar coordinate systems. By
default, AutoCAD expects us to enter values in absolute Cartesian coordinates,
distances measured from the current coordinate system's origin point. In AutoCAD 2016, the absolute coordinates and the relative coordinates
can be used in conjunction with the Cartesian and polar coordinate systems. By
default, AutoCAD expects us to enter values in absolute Cartesian coordinates,
distances measured from the current coordinate system's origin point. In AutoCAD 2016, the absolute coordinates and the relative coordinates can be used in conjunction with the Cartesian and polar coordinate systems. By default, AutoCAD expects us to enter values in absolute Cartesian coordinates, distances measured from the current coordinate system's origin point.