home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
Shareware Overload Trio 2
/
Shareware Overload Trio Volume 2 (Chestnut CD-ROM).ISO
/
dir30
/
mcadam.zip
/
OVERVIEW.TXT
< prev
next >
Wrap
Text File
|
1994-01-29
|
56KB
|
1,116 lines
CHAPTER 4.....OVERVIEW
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . 4-1
USER'S ANALYSIS. . . . . . . . . . . . . . . . . . . . . . . 4-2
FUNCTIONAL STRENGTHS OF MICRO CADAM . . . . . . . . . . 4-2
RELATED VIEWS. . . . . . . . . . . . . . . . . . . 4-2
SPLINES. . . . . . . . . . . . . . . . . . . . . . 4-3
SUPPORT OF GROUPS. . . . . . . . . . . . . . . . . 4-4
MORE EXTENSIVE DIMENSIONING CAPABILITIES . . . . . 4-4
ELLIPSES AND OTHER TRUE CONICS . . . . . . . . . . 4-6
FLEXIBLE LINE CREATION . . . . . . . . . . . . . . 4-7
USER FRIENDLY RELIMITING . . . . . . . . . . . . . 4-7
SIGNIFICANT CORNERING CAPABILITY . . . . . . . . . 4-8
SYMBOLS. . . . . . . . . . . . . . . . . . . . . . 4-9
ABILITY TO ROTATE THE WINDOW . . . . . . . . . . . 4-9
MULTIPLE USER-SELECTED ORIGINS . . . . . . . . . . 4-10
TEXT EDITING . . . . . . . . . . . . . . . . . . . 4-10
OPERATIONS BY COLOR OR LINE TYPE . . . . . . . . . 4-11
POWERFUL DISPLAY FEATURES. . . . . . . . . . . . . 4-11
RELATIVE ANALYSIS. . . . . . . . . . . . . . . . . 4-12
USER INTERFACE STRENGTHS. . . . . . . . . . . . . . . . 4-12
INPUT DEVICES FOR QUICK RESPONSE . . . . . . . . . 4-13
USER-FRIENDLY MENU STRUCTURE . . . . . . . . . . . 4-13
AUTOMATIC REPETITION OF OPERATIONS . . . . . . . . 4-14
ABILITY TO WINDOW DURING AN OPERATION. . . . . . . 4-14
EASY TO USE DRAWING FILE MANAGEMENT. . . . . . . . 4-15
"INTELLIGENCE" . . . . . . . . . . . . . . . . . . 4-15
SINGLE-SCREEN INTERFACE. . . . . . . . . . . . . . 4-16
EASY POINTS CREATION AND SELECTION . . . . . . . . 4-16
COLOR HIGHLIGHTING . . . . . . . . . . . . . . . . 4-17
EASY COLOR ASSIGNMENT AND MODIFICATION . . . . . . 4-17
QUICK, EASY SCREEN REFRESH . . . . . . . . . . . . 4-18
ACCEPTS MATHEMATICAL EXPRESSION ENTRIES. . . . . . 4-18
COMPATIBILITY WITH OTHER SYSTEMS . . . . . . . . . 4-19
CUSTOMER SUPPORT AND SOFTWARE MAINTENANCE . . . . . . . 4-19
CONCLUSIONS. . . . . . . . . . . . . . . . . . . . . . . . . 4-20
OVERVIEW
1. INTRODUCTION:
Both first-time PC CAD buyers and those looking to improve
upon their current PC CAD systems should make their purchasing
decisions with a firm understanding of what CAD should do in
their business. They must consider the kinds of problems they
want solved, the need to share data among groups or with
customers and suppliers, and the role of CAD, not only as an
engineering productivity tool, but also as a business tool.
The first test of any CAD system, is its ability to do real
work and to solve drafting problems. But issues such as
database management, communications, compatibility across
disciplines and across many sizes of computers are also
critical. In addition, issues such as customer support and
maintenance policies may not seem relevant until a user is
suddenly in trouble with a CAD system and needs assistance.
Thus, it is important to ask up front about a CAD company's
commitment to service, support, and software maintenance.
Other key questions about specific functional areas of a CAD
system are:
How does the system handle related sub-drawings and
views of a part or assembly?
Does the system allow me to continue to work and
think in a manner similar to the way I'm accustomed
to working?
Are there capabilities that make my job as an
engineer or designer easier?
Is it easy to change and edit drawings I've already
completed?
Can I enter and edit text easily? Can I specify
text parameters?
Are the drawing management and filing capabilities
easy to use and intuitive?
Beware of checklists. It is easy to accept the idea that
software packages can be effectively compared using paper
checklists with marketing buzz words and system-specific
jargon. A large part of a CAD system is difficult to describe
comprehensively. Without actually using a system or seeing it
in use, it is difficult to obtain an accurate and complete
understanding of its capabilities and imitations.
On the other hand, a checklist can be useful if one has
informed knowledge of the relative importance of particular
features or capabilities. The weighting of a checklist item
can be as important as whether the item is present or not.
Areas of analysis not easily subject to checklists include:
Human-computer interaction (dialogue with the
computer.)
Perceived versus actual need for supported
features.
Details of actions required to invoke given
functions (length, complexity, accessibility,
etc.).
Amount of data management imposed upon the user by
the system.
Level of concentration on the actual design/editing
process permitted by the system (i.e. types of
system distractions that require the user to focus
on entering information rather than on design and
editing processes).
"Circular functions"--functions provided by the
system whose need is generated only by inadequacies
of the system itself.
"Convenience functions"--simple methods for
accomplishing given tasks, although more complex
workarounds are also provided by the system (e.g.
grouping by color).
2. USER'S ANALYSIS
a. FUNCTIONAL STRENGTHS OF MICRO CADAM
i. RELATED VIEWS
A major functional advantage of MICRO CADAM is the
ability to create electronically related views of a
model, namely orthographic, auxiliary and sectional
views. Even today the basic key to manufacturing
is classic orthographic projection. This is still
the customary manner in which an engineer describes
to a manufacturer the details of what needs to be
built. In addition, the vast majority of
engineering drawings incorporate many views of a
part.
Less sophisticated systems may have documentation
and advertisements that depict two or more views of
an object positioned next to each other. However,
each of the views illustrated is usually a separate
drawing and completely independent from any others
on the drawing page. In actuality, without related
views such as those provided in MICRO CADAM, it
would prove to be a major undertaking to draw the
four standard views (plan, front elevation, side
elevation, and isometric) of any but the simplest
parts.
MICRO CADAM's AUX VIEW function and /ISO/ menu
option offer a significant advantage to MICRO CADAM
users. This capability is one of the most
important reasons why production CAD users use
MICRO CADAM as a serious engineering tool.
ii. SPLINES
Splines are mathematically accurate and easily
defined "irregular" curves. True splines have
special significance in engineering design. A
spline is the mathematical equivalent of the shape
that a flexible beam or rod will take when
constrained at the given points (the defining
points of the spline, with or without restricting
end vectors). This curve can be proven to minimize
the stress levels within a structure, given the
point constraints. MICRO CADAM splines maintain
second-order continuity, which is very important
when designing very smooth cross-sections and
surfaces.
Applications for splines extend throughout
industry, but they are essential for automotive
body design and aircraft work. A spline gives an
intuitively "better-looking" curve fit to an object
than does an arc-line curve, which are often
mistaken for splines. Arc-line spline
approximations have other disadvantages; mating
parts or clearances to other parts can be
inaccurate enough to be deceiving. Using MICRO
CADAM, parallel spline elements can be defined in
three steps--a feature that would not be practical
using approximations.
iii. SUPPORT OF GROUPS
Placing model elements into temporary or permanent
groups is an important capability of any CAD
system. This allows the user to perform a given
operation on all the elements within the group in a
single step, rather than repeating the operation a
number of times for each element. It is critical
for a user to be able to both easily create and
modify groups in order to facilitate model
construction. Three distinct capabilities
demonstrate MICRO CADAM's superior support of
groups:
(1) Creation of a group using an arbitrary
polygon. This feature allows the user to
indicate the vertices of an arbitrary polygon
to enclose the elements to be contained within
a group. This is particularly valuable when
other elements which are not desired in the
group lie in close proximity to other
elements. A simple rectangle may also be used
to define a group.
(2) Modifying a group. This feature allows the
group to be altered by either adding or
subtracting elements. A group that is created
using a rectangle or an arbitrary polygon
often contains elements that are not desired
in the group. This facility permits the easy
addition or subtraction to a group, aiding the
user in group definition.
(3) Sets (or permanent groups). It is often
desirable to place elements into a permanent
relationship with one another. This allows
the user to obtain information regarding the
elements within the set or to perform multiple
operations on these elements without
redefining the elements contained within the
group for each individual operation.
iv. MORE EXTENSIVE DIMENSIONING CAPABILITIES
In virtually all production engineering drawings,
dimensions are a critical component. The simplest
parts may contain as few as a dozen dimensions, but
a typical manufactured part contains scores of
dimensions absolutely necessary for definition of
the part. These dimensions are a vital
communication link between designer and
manufacturer. Without them many parts could not be
fabricated.
MICRO CADAM provides several methods for
automatically dimensioning elements that are not
available in other systems. The most significant
ones include:
/NORM/ -- Allows the user to dimension the
normal distance between two elements.
/CURV/ -- Allows the user to dimension the
curved length of any curved element.
/CHAM/ -- Allows the user to dimension
chamfered corners.
MICRO CADAM allows the user to create a dimension
by selecting any appropriate geometric element, not
just points. MICRO CADAM also allows the user to
redefine the location of the dimension at any time
during the creation of the dimension, and allows
many options for the placement of dimension text.
A few examples:
The user can define the horizontal as well as
the vertical placement of the dimension for
either horizontal or vertical linear
dimensions.
The user can indicate any location for
diameter or radius dimensions, independent of
the selection of the circle or arc.
In some other systems, a dimension is not an
entity, but rather a collection of standard
geometric and text elements: typically two lines
for the extension lines, two more lines for the
dimension lines, two solids for the arrows (a solid
is a four sided, area-filled polygon), and text for
the dimension. Once created, these elements have
no relationship to each other. On the other hand,
MICRO CADAM treats a dimension as a single entity
for such functions as moving, erasing and editing.
This saves time, because you don't have to select
elements one by one to change a dimension.
In addition to position editing, MICRO CADAM
possesses important dimension-editing tools. The
user is permitted to change the text, add a leader,
change the dimension lines, change the extension
lines, etc. Dimensions in MICRO CADAM are
associative (i.e. they are attached to the actual
geometry). A designer or draftsman needs to be
able to quickly and easily modify dimensions in
order to effectively document design alterations.
Without the ability to perform special editing
operations on dimensions, laborious workarounds are
needed, or the affected areas of the drawing must
be completely redimensioned.
MICRO CADAM also offers the functions /ERS DIM/ and
/NO SHO DIM/, which allow all dimensions in a model
to be erased or"no-shown" (temporarily hidden, but
not removed from the model). This ability to
conceal or erase all dimensions, either temporarily
or permanently, is very important. An extensive
set of dimensions can obscure the object being
drawn. In addition, in technical illustration and
general conceptual design work, it may be desirable
not to display the dimensions on the drawing.
v. ELLIPSES AND OTHER TRUE CONICS
Generating any complex curves with mathematical
accuracy requires a CAD system that offers curve
types beyond the simple circular arc. As with
splines, MICRO CADAM conics are very valuable
curves. They are commonly used for aircraft design
work. Using conics, a designer can easily and
accurately define smooth, cross-sectional curves of
aerodynamic surfaces. The ability to easily create
conics and modify them during their construction
(by selecting a tangent line, a shoulder point, or
keying in a ratio) provides the designer with great
flexibility. This allows significant control over
the behaviour of the curve, ensuring the cross
section is designed properly, and adequate
clearance for any internal features (frames,
struts, etc.) is provided. Using conics, the
designer can ensure smooth, complex curves which
maintain first order continuity of slope at their
intersections.
The ellipse is a member of the important family of
curves called conic sections. Conic sections also
include the circle, parabola, and hyperbola.
Ellipses occur in nature, such as in the orbits of
natural satellites. Ellipses are common drafting
elements found in many engineering drawings,
especially those that contain non-axial views of
holds and cylinders. A strong advantage of MICRO
CADAM is that it creates true ellipses, not
ellipses approximated by arc segments.
Some PC CAD systems use as many as sixteen arc
segments to define an ellipse, and the ellipse is
stored in the model as a concatenation of arcs.
The MICRO CADAM system stores the ellipse as a
single entity. This allows a true representation
and analysis of the geometry. MICRO CADAM also
accurately interprets a circle as an ellipse when
viewed in an isometric drawing.
vi. FLEXIBLE LINE CREATION
MICRO CADAM allows the user flexibility in the
creation of lines. In engineering design, the line
is a real workhorse. A CAD system designed as an
engineering tool should incorporate a variety of
methods for drawing lines. Three methods are
common to many CAD systems:
Define a starting point and an ending point
(Cartesian coordinates).
Define a starting point and a relative
distance (Cartesian coordinates).
Define a starting point, a length, and an
angle relative to the horizontal (polar
coordinates).
MICRO CADAM offers several additional techniques
virtually essential for the convenient construction
of lines. Some of these, which are fundamental to
MICRO CADAM are:
Creating an "unlimited" length line.
Creating a line that is parallel to another
element.
Creating a line that is normal to another
element at a given point on that element.
Creating a line that is tangent to another
element at a given point on that element.
Creating a line at a given angle from any
other line.
The items mentioned above (particularly the last
one) are critical functions which should be
contained in any CAD system designed for use by
draftsmen and engineers. MICRO CADAM also provides
similar abilities for the development of circles
and other elements.
vii. USER FRIENDLY RELIMITING
Relimiting is the ability to alter an element's
length, typically by having it lengthened or
shortened so it meets precisely with another
element. Relimiting is a fundamental CAD
procedure.
MICRO CADAM's RELIMIT function allows the user to
lengthen or shorten an element at will, using the
same function and even the same menu option. This
is one of the reasons MICRO CADAM's versatile
RELIMIT function has proven to be a powerful
editing tool. Additional advantages of the MICRO
CADAM RELIMIT function are as follows:
It is possible to extend or trim an element to
a point or "node", as well as a line, circle,
or arc.
A "break around" function is supported for
relimiting an element around another element.
A "break inside" function is supported for
relimiting an element within another element.
The user has the ability to "close" an element
(regenerate an element that has been broken or
relimited).
viii. SIGNIFICANT CORNERING CAPABILITY
Most manufactured parts have few, if any hard
corners. Corners and edges are often rounded
intentionally to reduce stress concentration that
can lead to premature product failure, and for
safety and cosmetic purposes. In addition, many
parts must have rounded corners and edges out of
manufacturing necessity, especially in the fields
of casting and injection molding.
The ability to automatically create a corner of a
given radius (including a radius of zero) between
two elements is a powerful tool for any CAD system.
It automates the task of placing a circular arc
tangent to two other elements and then relimiting
those elements to that arc.
A significant advantage of MICRO CADAM is the
ability to specify the quadrant (formed by the
intersection of the elements or the linear
extension of the elements) in which to create the
corner, rather than arbitrarily assuming the
direction the user intended.
MICRO CADAM's cornering capability also includes
the following enhancements:
/TRIM #1/ option--trim only one element, the
first one selected
/TRIM #2/ option--trim only one element, the
second one selected
/NO TRIM/ option--insert a fillet
/CONCAVE/ option--create a concave corner
radius
/PIGTAIL/ option--create a path for optical
trace following routers
ix. SYMBOLS
Symbols are integral elements in most engineering
drawings. The ability to place a commonly used
collection of elements quickly and easily at a
specified location on a drawing is a requirement
for virtually all types of drawings, including
mechanical, electrical or architectural.
In addition to offering many built-in geometric
symbols, MICRO CADAM allows the easy creation and
use of the following as symbols:
Arrows with text
Balloons with text
Deltas with text
Section arrows
Text-lines
MICRO CADAM also offers special symbol editing
capabilities, including:
Scaling
Rotating
Axis flipping
x. ABILITY TO ROTATE THE WINDOW
Without the ability to rotate the window, the user
is limited to panning and zooming. It is not
uncommon for a part to be designed with a number of
detailed areas with a non-horizontal orientation.
The ability to turn the window, possibly combined
with the capability of defining a secondary origin
greatly assists the user in both the defining and
editing of model elements. Without this
capability, the user is required to work at an
awkward orientation, quite possibly tilting his
head to gain a better perspective on the work area.
xi. MULTIPLE USER-SELECTED ORIGINS
It is often helpful (especially with large and/or
complex drawings) to place one or more additional
reference origins at critical points in the
drawing, possibly with a special orientation. This
allows the user to work from a much more convenient
axis block instead of having to reference every
drawing element from the true origin (0,0) point or
from some other previously-defined drawing element.
In addition, it is possible to construct multiple
views of a part at multiple scales using multiple
origins. This allows display of a part detail in
the same view at a different scale from the primary
view of the drawing; a number of auxiliary origins,
each with a different scale, can coexist in the
same view. Multiple origins also allow the user to
combine a sub-assembly in metric units with an
assembly in English units and then to dimension
everything in either or both systems. Multiple
origins are also useful for datum dimensions. By
defining a new origin, it is possible to use the
origin point as a reference for datum dimensions.
xii. TEXT EDITING
Most drawings contain text displayed in conjunction
with the geometry. The ability to generate and
modify text should be supported by any productive
CAD system. The purposes for generating this
textual information is varied. Text helps identify
elements in the drawing and often includes
manufacturing or assembling information.
Descriptive information pertaining to the drawing
as a whole, as well as to the designing firm, is a
requirement for virtually all production drawings.
MICRO CADAM refers to these elements as notes. The
editing capabilities provided by MICRO CADAM are
both powerful and diverse, including:
Text editing
Moving
Sizing
Altering the angle
Justifying
Fitting
Without these editing functions, the user may be
forced to erase the note and recreate it as
desired.
MICRO CADAM can also temporarily hide (no-show) the
display of notes in a drawing.
xiii. OPERATIONS BY COLOR OR LINE TYPE
MICRO CADAM supports a number of functions that
perform operations on model elements that share
specified characteristics. Several of these have
been discussed in earlier sections of this
introduction (erasing/no-showing dimensions,
showing symbols, and no-showing text). However,
several operations for elements of the same color
and line type are also important. These include:
Grouping by color
Showing elements of the same color
Showing elements of the same line type
For example a user may wish to change all the
elements of one color to another color (for
example, convert all of the blue elements to
green). This is a simple task to accomplish with
MICRO CADAM. In addition, it is often desirable to
display only elements of a particular color or line
type for verification purposes, especially when
preparing a drawing for plotting. By quickly
viewing only the elements of interest, the user can
assure that the model is correctly drawn and ensure
that it will be plotted accurately. This also
allows users to utilize colors as "layers" of a
drawing or to distinguish changes from previous
work on a drawing.
xiv. POWERFUL DISPLAY FEATURES
It is frequently desirable to temporarily remove
particular elements (both geometric and non-
geometric) from the display. By concealing desired
elements within the model, the user is able to
focus attention on a particular area of the screen.
Several specific applications of this capability
have been discussed in previous sections of this
introduction (dimensions, notes, elements with the
same color/line type).
In addition to being able to "show" and "no-show"
model elements, MICRO CADAM allows for quick and
easy erasure of all of the points or "nodes" which
have been created in the model. Since points are
typically used as model construction aids, it is
often desirable to remove them as they become
unnecessary. This allows the user to "clean up"
the drawing and frees valuable model space. MICRO
CADAM's /ERS PTS/ menu option allows the user to
immediately erase all of the points in the current
view with only three operations.
xv. RELATIVE ANALYSIS
It is often useful to obtain relative data
regarding two elements, particularly the angle
between two lines or the distance between two
elements. The ability to quickly and easily obtain
this information is an important feature of any
engineering-oriented CAD system. MICRO CADAM's
/REL/ menu option provides this capability.
b. USER INTERFACE STRENGTHS
CADAM was originally developed at Lockheed for internal
use by its own designers, engineers and draftsmen. Those
same people were responsible for defining the user
interface for the CADAM system. They insisted that
system developers retain the flexibility of the drawing
board with the precision and productivity of a computer
system. This challenge led to CADAM's unique and easy to
use interface. the MICRO CADAM user interface evolved
from that first effort. Over the years, system
developers have taken advantage of innovative and user-
friendly hardware options and have paid attention to
user's comments regarding the system. The result is a
user-friendly MICRO CADAM system that is consistent with
mainframe CADAM and PROFESSIONAL CADAM on engineering
workstations.
Research on interfaces has demonstrated that no single
type of interface is favoured among CAD users as a group.
However, users do show a marked preference for well-
structured, logical, and functionally consistent
interfaces. The MICRO CADAM system has combined a
logical menu structure (that can be represented by a
logical decision tree), clear English language prompts
and system responses, and a three-button mouse (or
tablet). Input from the alphanumeric keyboard is
minimal.
i. INPUT DEVICES FOR QUICK RESPONSE
The most productive configuration for Micro CADAM
uses three devices for input to the system: a
function key box, the alphanumeric keyboard, and a
3-button optical mouse. The function key box
allows the user to quickly select any major
function of the system. The function keybox is a
time-tested device that allows a user to enter a
function with the non-dominant hand. Thus, a right
handed user who is operating the mouse can quickly
use the left hand to change to a new function. In
addition, many users quickly learn to use the
function key box "by touch", just as they would use
a ten-key pad on a calculator. In addition, more
drawing area is made available on the screen
because a functional menu does not have to share
the display area. The alphanumeric keyboard is
used primarily for annotation and to input number
values with the ten-key pad. The mouse is used for
selecting menu options and drawing elements on the
graphics display. In addition, two system
functions--INDICATE and YES/NO -- in addition to
SELECT are implemented on the mouse. (The
INDICATE function allows the user to approximate a
location on the drawing. The YES/NO function is
used to confirm default values, cancel operations,
or repeat options, as well as other uses.) The
MICRO CADAM user is not required to memorize and
key-in commands--a laborious and time-consuming
process that requires accurate typing. Some PC CAD
systems unrealistically expect the draftsman to be
a proficient typist; this is not true of the MICRO
CADAM system, because user skills and expectations
were taken into account in designing the system.
The implementation of input devices for MICRO CADAM
places a large portion of the system function under
the user's fingertips.
PC CAD systems with overly complex and unclear menu
structures frequently employ a digitizer tablet
with template to spread the options out in front of
the user. At first glance, this may appear to be a
useful approach. However, the user may spend time
trying to locate and read the fine print on a
template and can become fatigued reaching across a
large tablet to select frequently used options.
ii. USER-FRIENDLY MENU STRUCTURE
MICRO CADAM uses an on-screen menu system. When a
function is selected, the system displays all of
the allowable menu options at the bottom of the
screen. Each menu option is accompanied by a
system prompt that tells the user what the
allowable input and actions are from that option.
In most cases, the user can complete the desired
operation from the primary menu option. Rarely
does the system require the user to delve more than
two layers deep into a menu. In addition, the user
can exit from any function at any time.
Other PC CAD systems may require the user to deal
with multi-level, complex menu structures. Menus
may have several entry points. Others cluster
their options into two or more groups, and the
steps required to move from one function to another
unrelated one can be unclear, unless the user goes
back to the primary menu and works down again in a
different direction. It is not unusual for a user
to move up and down through the various menu
levels, resurfacing at the primary menu level to
reorient himself and then move down again. In
addition, the system may display menu options that
are not available to the user at the current level.
iii. AUTOMATIC REPETITION OF OPERATIONS
Creating a complex drawing often requires certain
operations to be repeated. Command driver systems
typically require the user to reselect a function
or menu option to repeat an operation. This can be
time-consuming and annoying.
MICRO CADAM's unique YES/NO function allows the
user to repeat an action by pressing a single
button on the mouse. In addition, after an
operation is completed, the system automatically
restarts the sequence until the user interrupts the
cycle by selecting another menu option or by
pressing a function key.
iv. ABILITY TO WINDOW DURING AN OPERATION
A CAD user frequently finds it necessary to alter
the drawing window (or viewport) to construct or
modify a model. This is an especially important
function when the user is working with small PC
graphic monitors. MICRO CADAM's WINDOW function
allows the user to zoom in and out on specific
areas of a drawing. This allows him to use a small
monitor to draw very large and complex drawings.
In addition, the MICRO CADAM user can change window
size or orientation in the middle of another task
and resume the task at the point where it was left.
Also, the MICRO CADAM system "remembers" up to
seven window positions that can easily be recalled.
Other PC CAD systems may lock a user into a task or
sequence of tasks until all the steps are
completed. Thus, the user must complete or abort
the operation before the drawing window can be
modified.
v. EASY TO USE DRAWING FILE MANAGEMENT
MICRO CADAM makes it easy to access, delete, copy,
and rename drawing files that have already been
created, even if the user has forgotten the name
(or the spelling) of the model.
To access a drawing in MICRO CADAM, you simply:
1) Key in a group,user which contains the drawing
file of interest.
2) Since the /CALL/ menu option (which initiates
the calling sequence) is the default, press
the Y/N function key to obtain a complete
listing of your files. View the list and
determine the name of the file in which you
are interested.
3) Select the name of the file you wish to call.
This requires significantly fewer steps than many
other PC CAD systems. Similarly, deleting,
copying, and renaming files are simple,
straightforward procedures in MICRO CADAM. Easy
manipulation of the drawing file data base is an
important productivity tool not found on many PC
CAD systems. Long filenames make it easy to
recognize drawings.
vi. "INTELLIGENCE"
MICRO CADAM interacts intelligently with the user.
This is evident in the way in which the computer
carries on a dialogue with the user. Most CAD
systems require the user to prepare the system for
the exact form and sequence of the data to be put
into the system.
The MICRO CADAM user is typically permitted to
enter information into the system without
explicitly informing the program of the exact
nature of the data. The software analyzes the
information and "decides" on its own the precise
significance of the data. That is, the MICRO CADAM
user can communicate with the system on a more
natural level, providing it with detailed
information and allowing the software to interpret
it.
In some other systems, the computer must be
informed in advance of the precise method being
used to define entries (such as the several ways to
define a circle). MICRO CADAM, on the other hand,
anticipates the user's actions whenever possible,
frequently permitting data to be entered with
little or no "prefacing remarks". The user is able
to work with the software, allowing it to make as
many "decisions" as is practical. Thus, MICRO
CADAM attempts to incorporate many features of
human-human dialogue into its human-computer
interface.
vii. SINGLE-SCREEN INTERFACE
MICRO CADAM has been designed to effectively use a
single screen; no additional monitor is necessary.
All of the information which a user needs or
requests is displayed around the perimeter of the
graphics screen. This allows the user to more
easily relate the data supplied by the computer to
the drawing and permits uninterrupted concentration
on the task at hand.
Some PC CAD systems are designed to be used most
effectively with two monitors. One screen is the
graphics area, with the menus located down the
right-hand side and several lines at the bottom to
serve as a combination message area and command
line. The second screen contains most of the
user/computer dialogue, analytical data requested
by the user, and other information which is too
bulky to fit conveniently in the graphics area
(such as user HELP listings).
However, requiring the use of two monitors is a
bulky, ineffective design for a CAD system designed
for a micro computer, and can be costly. When a
system combines two screens into a single monitor,
using a PF key as a "toggle" between them while
internally keeping track of both, the user must
flip back and forth to view the graphics area or to
set up command sequences.
viii. EASY POINTS CREATION AND SELECTION
Points are the basic building blocks for other
geometric elements. A user often needs a visible
marker at a significant location on the screen that
can be referred to repeatedly within a drawing
session. By placing point elements on the graphic
screen, the user can accentuate areas of interest.
The exact location of interest can be seen without
any approximation. (For example, the midpoint of a
line or the center of a circle can be easily
designated.) It is essential that a CAD system
allow easy generation and use of points.
MICRO CADAM points are simple to create and
reference. Once a MICRO CADAM point has been
defined, it becomes a visible part of the model and
remains until it is erased or no-shown. A single
operation allows the user to create a point.
Although virtually all other elements (arcs,
circles, ellipses, lines, splines, etc.) include
within their definition one or more points, other
PC CAD systems do not allow these points to be
referenced by selecting them with a pointing
device.
ix. COLOR HIGHLIGHTING
Most CAD systems support some type of element
highlighting. This important feature is used to
single out the element(s) detected by the system.
It is therefore vital that a CAD system support a
highlighting capability that dramatically alters an
element's physical appearance while preserving its
integrity.
Many MICRO CADAM operations (such as grouping,
analyzing, editing, etc.) use highlighting to
identify model element(s) on which the system is
currently operating. This tells the user that the
element(s) picked have indeed been selected and
allows him to continue the process in progress or
alter it as required.
MICRO CADAM alters an element's color to accomplish
this task. Thus, while the element's appearance
changes, it maintains its geometric integrity. In
addition, MICRO CADAM supports a user-selectable
highlight color.
x. EASY COLOR ASSIGNMENT AND MODIFICATION
Color support is invaluable for today's state-of-
the-art CAD systems. The ability to quickly assign
and modify the colors of model elements is desired
by many CAD users. MICRO CADAM's "side" color
display provides a superior method for assigning
and modifying element colors from within a work
session. The user has a large pallet of colors
from which to choose, and changing the color of an
element (or setting the color mode) requires a few
simple operations. The user can visually examine a
hue before assigning it to a model element without
the use of the keyboard.
Some PC CAD systems allow the user to assign colors
from a color pallet, but from outside a work
session. Thus, the user may have to remember color
numbers or leave a session to check or modify color
assignments.
xi. QUICK, EASY SCREEN REFRESH
Most PC CAD systems require the user to refresh the
screen occasionally in order to "clear up" the
drawing. This "housekeeping" operation should be
easily accessible and quickly executable.
Since refreshing the screen requires excessive CPU
time, most PC CAD systems do not automatically
refresh the screen after each operation (except for
certain functions, such as windowing). However,
this task needs to be performed following extensive
editing of the model elements. MICRO CADAM
provides an extremely convenient method for
accomplishing this task: a programmed function key
(PFK3) has been allocated for the purpose of
refreshing the screen. This key is always
accessible and can be pressed at any time during
the modelling session without interrupting the
current operation.
xii. ACCEPTS MATHEMATICAL EXPRESSION ENTRIES
MICRO CADAM allows the direct entry of mathematical
expressions to help define geometry. It is often
convenient to use mathematical expressions to
define a numerical value. This eliminates the need
to manually solve an equation (using pencil and
paper or calculator) and then key in the solution.
There are many applications for this feature. The
placement of model elements at specific locations
in a drawing typically requires the user to
reference existing elements. The user frequently
finds that he must generate a simple mathematical
expression relative to the present geometry and to
the element(s) he desires to create. Sometimes
these calculations are too complex to perform
mentally. If the CAD system permits him to enter
an expression, it can be of significant assistance
any time the user is required to add, subtract,
multiply, and/or divide in order to arrive at a
single value.
c. COMPATIBILITY WITH OTHER SYSTEMS
There are many approaches to the problem of compatibility
with other CAD systems. It is difficult to write
programs that not only translate the elements of a model
in one system to the format of another, but also retain
the intelligence and unique features built in to the
model. This is one reason that translation software
based on the IGES standard has generally been
unsuccessful. Because there is rarely, it ever, a one-
to-one correspondence between the features and functions
of two different CAD systems, something is invariably
lost in translation.
ALTIUM INC. (formerly CADAM INC.) has approached the
problem of translating drawing models from one system to
another in three ways:
i. The Data Transfer Option allows drawings to be
downloaded from mainframe CADAM to MICRO CADAM and
uploaded from MICRO CADAM to mainframe CADAM. This
allows the user to move drawings created on MICRO
CADAM to mainframe CADAM or PROFESSIONAL CADAM, and
to take advantage of additional functions and
applications packages.
ii. Users and third-party software vendors have a
window into the MICRO CADAM database through the
Geometry Interface Option. Geometry Interface
allows you to write FORTRAN programs that can
access the MICRO CADAM database--geometric and
nongeometric entities can be edited, extracted
from, or added to a MICRO CADAM drawing file.
iii. The DXF translator allows drawings from competing
CAD systems to be brought into MICRO CADAM, and
drawings from MICRO CADAM can be sent to other CAD
systems.
d. CUSTOMER SUPPORT AND SOFTWARE MAINTENANCE
Some low-priced PC CAD vendors sell their software on an
"as is" basis. That is, the product the customer
receives is not subject to maintenance updates or bug
fixes and, normally, the software vendor is not available
for consultation on installation and use of the product.
There is a trade-off between price and functional
integrity, reliability, and ease of use.
ALTIUM INC. (formerly CADAM INC.) strongly believes that
a customer is entitled to a reliable product that is easy
to use. They are committed to the constant improvement
of the MICRO CADAM software, including functional
enhancements and improvement of any functional
deficiencies. The commercial version of MICRO CADAM
continues to be enhanced.
3. CONCLUSIONS
Setting aside MICRO CADAM's ability to link directly with
other members of the CADAM family, MICRO CADAM's pure
engineering advantages over other PC CAD systems can be
summarized as follows:
MICRO CADAM has:
Superior capabilities for relating subdrawings and
for viewing the part
More types of elements meaningful to engineers
More ways to create elements
Quick and easy editing of graphic elements
Complete and flexible text facilities
Superior dimensioning capabilities
More direct access to points
User-friendly data management facilities
A significant advantage of MICRO CADAM is that it is fully
compatible with mainframe CADAM. This is very important to
current mainframe CADAM users, to those companies large enough
to be planning the acquisition of a mainframe system or UNIX
workstation in the future, and to those who have direct
dealings with contractors and vendors who use CADAM. MICRO
CADAM is also a productive tool for smaller design and
manufacturing shops that perform a myriad of technically
creative tasks.
Before purchasing a CAD system, it is a good idea to actually
sit down and work with the system. A "canned" demonstration
can be misleading. The bottom line advantage of MICRO CADAM
is "more drawings per hour".
The CADAM family of products offers a compatible set of
CAD/CAM tools across many industries and disciplines,
supported on machines ranging from the single-user PC/AT to
the RS6000 to the 200-plus user IBM 3090 mainframe.
Overall, MICRO CADAM is a superior engineering tool, and its
use will incur productivity gains for the user. The
tremendous amount of CAD/CAM experience which has been
incorporated into MICRO CADAM is readily evident upon working
with the system. Years of dealing with demanding users have
fine-tuned the product into a powerful and productive software
package with proven reliability. A careful review of the
functional capabilities of other PC CAD systems will convince
a prospective purchaser that MICRO CADAM is the best system on
the market today.