INTRODUCTION TO THE MECCAID LIBRARY The Meccaid library has been created with an Isometric 0.25" grid as the basic grid setting, using an imperial scale. The drawings of the parts are based on a sample of genuine Meccano parts taken from the author's collection. With so many part variants produced over the years, there has had to be a compromise. For example, the larger strips, (7.5", 9.5" and 12.5" strips) as well as having varying thicknesses, also have ends that vary between half round and semi circular. In the Meccaid library, therefore, parts have been given 'standard sizes' using the following parameters. Strips, angle & flat girders .030" Curved strips, flat plates .030" Braced girders .020" Flexible plates .010" Spur gears .060" Large circular parts .050" They have also been set up so that overlapping parts will 'fuse' into each other. If parts separation is required, then the part will have to be moved by the appropriate amount. When the library is installed, it will be seen that, in general, each part is located in a separate file, the name of which will be the Meccano part number, preceded by a five and a series of zeroes. Thus, for example, file 50006A.TVL will contain the 1.5" strip and various nuts and bolts. However, some parts fell naturally into a combination library and these parts are identified with a file name ending in a 'Y' or 'Z'. An example is the 1" pulley, with and without boss. These parts are contained in the one file 50022Z.TVL. It will be found therefore, that parts requiring a boss, such as pulleys, gears, etc. will have the part drawn without the boss, the boss being contained within the library. When the boss and part have been placed in the drawing, the two parts can be selected and grouped together to create a single part. In the interests of storage requirements, each library contains the minimum number of projections, from which it should be possible to obtain any other projection using the library 'rotate' facility, or (in the case of nuts and bolts) by the 'Y' reflection after placing the part on the page. If this is found to be inconvenient, and storage is not a problem, then once the part has been rotated and reflected to its desired position, then the part can be stored back into the library, using the READ SYMBOL FUNCTION from the LIBRARY MENU. The library must, of course, be saved afterward! Again, if a large amount of memory is available on your PC - greater than 4Mb - then it may be found more convenient to create a multiple part library. As each library can contain up to 900 symbols, then it is quite feasible to create multiple part libraries, although it must be remembered that on loading the library, it will need to share the available RAM with that required for the drawing. When a part is selected in the library, the preview window will have a small blue dot, usually located at the centre of the part. This represents the anchor point of the part - the point that was selected when the part was stored in the library. It also depicts the anchor point of the part when placing it on the page. On selecting the part from the library, a red rectangle will depict the area of the part and the crossover position of the cursors will indicate the actual anchor point of the part. It is this anchor point, and the isometric grid locking, that ensures that line up of the parts is both easy and convenient. A simple regular part, such as a strip, requires only the one basic projection, although for convenience, the 'Y' reflection is also contained within the library. However, the more angular parts require more than one projection. Angle girders, for example, have eight projections. From these eight, it is possible to obtain any of the twenty four possible projections of the part in question. The files on this Meccaid demonstration disk contain a suitable selection of parts that enable simple models to be 'constructed'. The selection also contains extracts from the main library of spur gears so that some experimental gearboxes can be built. The gears included enable ratios of 1:1, 2:1 and 3:1 to be obtained at the standard Meccano spacing of 0.5". The sample drawings and settings included on this disk are: GIRDERS.MPG Displays how the 24 required projections can be obtained from the 8 contained within a library. TRUCK.MPG A small 6-wheeled modern tractor unit. There are sufficient parts on this disk to enable it to be rebuilt. STER_BOX.MPG The main steering, clutch and brake mechanism from the Author's Midland Red S15 bus (Available as a Modelplan from M.W. Models of Henley-on-Thames). This demonstrates how the layer function of TSCAD can be put to good use in designing complicated mechanisms. COLORS.MPG A simple drawing that shows the advantages of the colour libraries, available in current French yellow, blue and silver; and in the Liverpool mid-50's colours of medium red and green. On installation, the drawings will be placed into a subdirectory \MECCAID of the TSCADRAW\DRAWING directory and the libraries will be placed in a similar subdirectory in the TSCADRAW\LIBRARY directory. The storage requirements for the contents of this disk are: 36 Library files: 1.38Mb 8 Drawing files: 745Kb The complete MECCAID package (compressed onto 5 high desnity disks!) contains hundreds of symbols for (almost) all of the parts available in the Meccano construction system, and a 36 page user guide. Additional colour libraries are also available. See the file ORDERFRM.TXT for ordering information. The Meccaid library is (c) Roger Wallis - 1994