Computer Aided Design (CAD) Techniques in Railway Modelling
The earliest CAD systems were introduced to automate aspects of traditional drawing board work. For example, design changes could be implemented without the tedious business of scratching out part of the original design, restoring the paper surface and drawing in the revisions. Multiple copies of design elements could be made readily or complex shapes produced in different sizes (parametric design).
Output was typically by converting the drawing file into g-code (a language that tells computerised machines to do something), the g-code was then sent to a pen plotter that drew out the design automatically.
The parallel development of computerised control enabled CAD systems to be directly connected to machines, a system known as CAD/CAM (computerised design and manufacturing), the predominant manufacturing technology used today.
What has this got to do with railway modelling?
This technology, once the exclusive province of well capitalised high tech manufacturing, is now very affordable and commonplace.
There is a wide range of CAD systems available that can be run on the typical home desktop computer or laptop. (a quick internet search found 22 different open source CAD systems, mostly free to use). Similarly there are many desktop manufacturing technologies suitable for our hobby. These include vinyl and laser cutters, 3d printers and CNC machine tools. There are also on-line 3D print bureaus that can produce objects from suitable CAD files.
The widespread availability of the essential components of CNC machines such as stepper motors and programmable logic controllers (PLCs) has encouraged the growth of on-line communities devoted to self building of CAM machines of all types.
These machines can be obtained in a range similar to that of model locomotives; from take it out of the box, plug it in and use it, through very well designed and comprehensive self build kits to a scratchy set of drawings and shopping list.
CAD/CAM is mainly concerned with the design and production of 3D objects. For the railway modeller there are other aspects of computer aided design that are also useful, these include graphic design, layout design and programs to produce detailed templates for building pointwork.
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