should be available for delivery in September. At the tine of
writing (mid June) the prototype is operational, but some
refinements and further testing are required.
Firstly we must put the facilities offered by NAS-CAD into
perspective. Full function commercially available three
dimensional computer aided drawing systems generally cost over
£100,000, and even low-cost 2 and a half dimensional systems
generally cost around £50,000. NAS-CAD as a complete system of
hardware and software will cost around £3,000, and does not
pretend to offer all the features of systems costing more than
ten times as much. Nevertheless it is a completely practical
system which can be used in preparing technical drawings,
layouts, scheme drawings etc. It can handle up to about 3000
lines per stored shape or object. These objects can be stored
on disc and then recalled, thus allowing standard objects to be
incorporated in a drawing.
NAS-CAD is used with two monitors (or a monitor and TV). One is
used for the picture output from the
AVC, while the other
displays the 48 x 16 text display. The latter is used to
display the menu of commands available. There is a main menu of
operations which can be performed, specifying a particular
option results in the appropriate sub-menu being displayed.
Commands are typed in using the keyboard, which is also used to
specify scaling factors, angles of rotation etc.
The graphics screen is used to display the drawing being
produced, to a resolution of 380 points horizontally by 256
vertically. A large cross indicates the current cursor
position, and is referred to as the graphics cursor. This
graphics cursor can be moved around the screen using the normal
cursor control keys, although in this case the cursor is of
course defining a single pixel at the intersection point. The
cursor can easily be positioned to an accuracy of a single
pixel, and its current screen co-ordinates will be displayed on
command. For fast movement of the cursor the GRAPH key is held
down while the cursor control keys are pressed. Points, lines
and polygons can be drawn and saved on disc, or recalled from
disc and positioned anywhere on an existing drawing. The whole
drawing, or a re-loaded object, can be magnified or rotated as
required. Colour can be used in the drawing, or colours can be
Any drawing can be modified at any time quite easily. Text,
including dimensioning can be added to a drawing.
The full version of NAS-CAD described above is an extremely
powerful package and has required substantial development time.
This will probably be reflected in the price, but a more modest
version at a correspondingly modest price for the enthusiast or
educational User will probably also be available retaining the
main features of the program. We will give more technical,
marketing and availability information in the
next issue of Nascom News.