20 Chapter 2
tural units, engineering units, scientific units, and surveyor’s units. These units can be represented in
various formats commonly used by professionals.
When working with engineering units, the designer or drafter can specify whether all the dimensions
should be represented in inches, feet-inches, centimeters, or meters. Angular units of measurement
such as decimal degrees, minutes, seconds, or radians can also be chosen.
In general, when there is a need to work on a large-scale drawing such as a plan of a township, a
high degree of accuracy may not be warranted, and it may be decided to set a lesser degree of accu-
racy—say ,1 foot, 0 inches. The computer will then round off all the measurements to the next foot, which
avoids the use of any fractions less than a foot. Where minute detail is required, a higher degree of ac-
curacy such as 1/8 or 1/64 inch may be set.
Drawings Storage and Access.
As previously mentioned, it is simple, quick, and convenient to generate or organize a CADD drawing on
a computer. Most computer hard drives have the capacity to store thousands of drawings (and this storage
capacity is continuously increasing with advancing technology), and they can be opened within seconds.
Some of the advantages of a computer’s electronic filing system over traditional filing include:
- It enables and encourages the creation of a highly organized and efficient environment.
- It contributes to large reductions in general working space.
- An electronic drawing does not age or become faded. Whenever a new drawing is required, it
can be printed from disks. (It is important that the program used to store the CADD files be reg-
ularly updated to avoid becoming obsolete. With continuously advancing technology, some stor-
age methods have already become outdated, such as zip drives and some types of disks.)
Through networking electronic drawings can be shared by several users, allowing them to coordi-
nate their tasks and work as a team. Different professionals such as architects, engineers, and construc-
tion managers can use the same electronic drawings to coordinate building services. When a modifica-
tion is made to a drawing, this information becomes instantly available to all the team members. It has
thus become far easier to share information. Professionals located in different cities or countries can now
instantly transmit electronic drawings to one another. They can also publish these drawings on the In-
ternet for anyone to access. Most CADD programs incorporate special functions designed to allow you
to export drawings in a format (such as .gif or .jpeg) that can be viewed on the Internet.
Project Reporting.
The computer is an ideal instrument for generating project reports, cost estimates, and other business
documents. CADD’s database capabilities include the ability to link specific nongraphic information
(such as text or financials) with the graphic elements of the drawing. The nongraphic information is
stored in a database and can be used to prepare reports.
An architect, for example, can attach text attributes associated with the door and window symbols
in a drawing. These attributes include the door’s size, material, hardware, cost, and so forth. Equipped
with this information, the computer can then automatically generate a door schedule listing all the doors
and windows in the drawing!
Nongraphic information is directly linked with the graphics on the screen so that, when a change is
made to the drawing, the values in the reports are automatically updated. This provides a useful means
to manage large projects from design through project completion.