How do we get from an idea to a finished part?
It should be clear that we first need a drawing of some sort that describes the shape and its dimensions. The software that is generally used for that purpose is called CAD (Computer Aided Design). The best known program is AutoCAD. There are many other programs.
However, I use Corel Draw which may cause some readers to shake their heads. Corel Draw is not really a CAD program. Then, why do I use it? I have used Corel Draw for more than ten years and have generated thousands of drawings. The drawings ranged from furniture design to templates for etching circuit boards. I know the program in and out and I can whip together a drawing in no time flat because of many years of experience.
I often use many layers in a design, some used just for studying a layout, others for dimensioning, tracing a picture, overlay comments and the like. Now, in view of CNC machining, I can also add a layer with just the shapes to be cut.
Corel Draw strictly uses vectors to describe shapes. That means a drawing can be scaled over wide ranges without distortion or losing details.
Let’s follow the steps that will result in the tray shown below.
A Layer in Corel Draw was made that contains only the bare curves of the tray.
There is a potentially disastrous problem with shapes that were assembled from various primitive elements. Yes, Corel Draw can join the elements into a single entity. However, that doesn’t mean that the curves are closed which is a prerequisite for the next phase.
Closing a curve in Corel Draw is possible but it can be a tedious undertaking. Basically, one can test for a curve to be closed by selecting AutoClose in the curve editor. A curve will always ”autoclose” but the result may look quit different from what you expect. If that is the case, one has to inspect all nodes of the curve and properly join adjacent nodes.
Three cups of coffee later, you will eventually succeed.
Do not attempt to proceed until all curves are closed
The final step in Corel Draw is scaling the shapes shown on the left to the actual dimension (16 inches in diameter in our example) and turn on the visibility and print flag for that layer only. Don’t worry when the final drawing size exceeds the normal paper size. Then, export the result as a DFX file (AutoCAD file type).
If you use and have the experience with a real CAD program, you will not have to deal with the steps mentioned above.