Nascom News­let­ter

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 altered.

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.