Page 279 - CITS - ED - Mechanical

ENGINEERING DRAWING - CITS

• Special features.
Draw: The draw module provides access to all the drawing functions of CADD. Whenever you need to draw
something this group of functions is used. The draw module enables you to draw lines, arcs, circles, ellipses, text,
dimensions, symbols, borders and many other drawing components.
Draw is CADD s most frequently used module because all drawing work is accomplished using it.
Edit: The edit module lets you change existing drawing elements and manipulate them in a number of ways. You
can move, copy or erase drawing components. You can enlarge or reduce the sizes of diagrams or change the
colour and line type of drawing components. You can also change the size and style of text and dimensions, as
well as edit a dimension to show different units of measurement. A good CADD program is designed to change
the appearance of all drawing elements created with CADD.
The edit functions also act as convenient drawing-aid tools. They enable you to join missing corners of lines, trim
drawing components along a line, stretch them to fit a new shape, etc. The list of editing capabilities goes on and
on. The edit functions make CADD a dynamic drawing tool.
Data output: The data output module enables you to display drawings on the screen and then print them on paper.
There are two separate sets of functions that help accomplish this:
• View-display functions.
• Print/plot functions.
The view-display functions allow you to display different views of a drawing on the screen. These functions are
used quite often, because every time you need to draw something or edit something, you need to focus on that
portion of the drawing. With the help of view-display functions, you can zoom in on a specific portion of the drawing.
The print and plot functions allow you to print drawings using a printer or a plotter. You can control many aspects
of printing and plotting. You can print the same drawing in different sizes by applying the appropriate scale factor.
You can plot the drawings with specific colours, pen thickness, and line types.
Data storage and management: The data storage and management module allows you to store and manage
drawing data. Through the use of the functions in this module, you can store drawings as files on the hard disk.
You can manage the files in directories and sub-directories, and move, copy or delete them as needed.

CADD data management functions also let you translate drawings created by other CADD programs.These functions
convert drawing data to a generic format that can be read by any CADD program. Data exchange format (DXF)
is one of the common data translation formats used by CADD program. There are a number of data exchange
formats available.
System control: The system control module (also known as system defaults) allows you to control how CADD
works. CADD programs are designed for a broad range of professionals, including architects,designers, engineers
and surveyors. With the help of system control functions, you can set the working environment of CADD to suit
your needs.
Example: You can set the type of units that you will be using, the accuracy of the units, a style for dimensions
and text, colours, layers, line type in a drawing, etc. Additionally, you can customize screen menus, the display of
colours on the screen, resolution of the screen, size, the speed of the cursor, etc.
You can also specify whether the selected defaults should apply to a single drawing, to a specific project or to all
the projects in a specific category. The defaults can be set on a temporary or permanent basis.
Special features: CADD programs usually offer a number of special features that make working with CADD easier
and allow you to automate many drawing tasks. For example, you can create layers in a drawing that allow you to
segregate drawing components. You can develop spreadsheets and databases that can be used to create many
types of project reports. You can create three-dimensional (3D) drawings, such as isometrics and perspectives,
with the help of 3D functions. You can also accomplish many other automated tasks with the help of macros.
The number of special features a CADD program has or how elaborate they are various from one program to
another. Some vendors sell specialized features as separate packages, while others include them in a single
package. It all depends how a program is written, how big or small it is, and how it is sold.
CADD user interface: CADD user interface provides the environment and the tools that allow you and the computer
to communicate. Each CADD program establishes an environment that best suits its purpose. The goal is to make
working with CADD efficient. Most programs use a Graphic User Interface (GUI) to communicate with the user. The

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CITS : Engineering Drawing (Mechanical) - Exercise 12