I'm real new to all of this, so bear that in mind as you read. I have never used a CAD program before. I chose DraftSight. Like any new software, it takes a little time to learn, but there are many tutorials for this application, and that's a big help. It's also true that the more software you learn, the more "intuitive" the next app is to you.
When communicating with math, there is no language barrier. A CAD program is basically a way to do that in that by using it's interface, you can manipulate the geometry and all the related calculations with a relatively minimal knowledge of the mathematics required. While CAD programs help you make illustrations which will help in human to human communication (one picture is worth a thousand words), their output is essential for use with laser cutters, plasma cutters, CNC routers, and so on. If you don't present a finished CAD drawing, you'll have to pay the laser cutter to do that. Not only can that get expensive, but the risk of error may be greater, especially when communication is difficult for one reason or another.
DraftSight allows you to manipulate the geometry by using your mouse. If there's an easy way to achieve the precision that's required using this method, I haven't found it. It also gives you a command line in the lower left corner which prompts you to make the next step. But if you want a line of a precise length, or a precise angle, or radius, using the command line is both relatively easy to learn, and extremely efficient.
Photoshop is primarily a raster drawing tool. That means that all your work is pixilated. If you try to enlarge or reduce dimensions, something is lost. You can test this by selecting the single row or column marquis tool to draw a 1px wide line across your canvas. Fill that marquis with a color that contrasts with the background color you used. What happens when you enlarge your image by varying amounts; be sure to look at an increase in image size by just 1 px. Zoom in as far as PS allows; what do you see?
PS does include a pen tool, and that, like the pen tool in Illustrator, is a vector drawing tool. Do the same experiment as above with a single line you draw with the pen tool. When you zoom into your vector drawing, what do you see then? I believe that as long as you don't rasterize it, you can save it as a vector. At best, though, the precision the laser cutter software needs is challenging to obtain in PS. It's like, you can drive a small nail into wood with the handle of a screwdriver, but a hammer makes the job so much faster, and cleaner. I'm also not sure if PS will save in a file format a laser cutter can read.
If this is about making just one drawing for a single keyboard design, then maybe it's not the best use of your time to learn a CAD program like DraftSight. If you like learning new stuff that can be applied in other projects later, then learning it makes a lot of sense. These drawings are relatively simple, too; there is no third dimension to deal with. Help is available in many places, including Geekhack. DraftSight also has it's own forum, although it can be a bit technical. YouTube has a large volume of tutorials for using DraftSight, and I learn most easily by watching other people.
Dave ☮
I suggest downloading one of the open source designs, then you can measure it. Phantom or GH60 should work.
already sir,i download phantom.dxf how to edit sir on DrafSight? looks complex
any tutorial make with photshop? actually i can edit design plate sir.jd/matt30 though not neat
but i not sure they (laser cutting) workers understand