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Week 01: Computer Aided Design

Phase 0: Old friends

A long time ago in a city far, far away... (Roughly 2000 in Munich, OK, not that long ago) The world was still simple. I was at school, doing the rather mad school project of building an enigma machine. Yes, that crypto machine. Not a replica, it didn't look a bit like the original, it was just supposed to work, not to look great. Madness, but I had brought that upon myself.

Building the parts for that more or less required me to get into CNC fabrication. Which was a problem, until I found out that the local model railway club had a small, old CNC mill that could do it. I just needed to draw the parts. Which had to be done either in AutoCAD or in a really bad, cheap knock-off I had access to. I learned to think flat, and to repair what bits of g-code the export could throw at me. The enigma worked, in the end. It broke down just during the final project presentation.

At the uni, my first 3D CAD experience was... hopeless. If you ever have the idea of running Catia on a computer that has been thrown away by another department... Just don't.

A little while later I learned (at another uni) to work with Inventor. It has its quirks, every CAD solution has, but it has served me well even for my first job. It's expensive, though.

Phase 1: The world is flat! - 2D CAD

The gimp

A lot has happened to this one since I last had a look at it. Some years ago, when mostly working with a rather old version of Paint Shop Pro I was annoyed about some file format not opening there and had a look at gimp. To be polite, I was horrified. It did open that file, though.

I was reluctant to pick it back up after that experience. The nice tutorial by our "local" guru ferdi did help, though. Switching the user interface to one-window mode greatly helps against the clutter older versions left on your screen (and against the tool window you need always being obstructed). I played around, then came to actually doing something approaching my final project - an awful graphic of why I find our commercial pick-and-place hard to use:

Yes, I know the colours clash. It looks downright awful. I should have used a new layer for scribbling my comments and then changed that... well, too late now. More on the project can be found in the update page on my final project.

On the downside, a few problems remain. Loading gimp is a horribly slow affair, and it still can't handle 16 bits per channel colours. Which is why it can't really handle the output of our digital camera.

In the end, my personal conclusion is that I have found a new tool to use, so it's a good thing I tried.

Why...?!?: Inkscape

Why oh why...? Inkscape could be a really fine tool for (not only) vector drawings. It is not, though. Someone stopped half-way there when programming the geometry handling, which is a horrible mess. Shutting off all options in the 'transformation' subtree lessens the pain, but that's about it.

I did draw a simple overview of my placer project to give it a chance. I'll leave it at that.

The svg-file is also available, of course.

Phase 2: That lump of data over there! - 3D CAD

Work in progress - FreeCAD

FreeCAD has come a long way since I last had my hands on it. It still has some bugs (like lines in sketches on an existing surface vanishing in the rendering) and some inconveniences when coming from other CADs... but it actually works quite well now. That is, you can do a lot of stuff and it works. It even supports my 3D mouse nicely. Development seems to be in continuing progress, so this is one project to keep in mind.

FreeCAD-file. Obviously, that's not much yet, and running into the different-to-inventor UI paradigm they use was no fun. But it works, and it's free enough that you can even tinker with it if you want, which is a cool thing.

One test that is still open is to compile it myself to get 3D mouse support in the mac version.

Big ole Solidworks

Solidworks is the standard CAD solution of our uni, so I will have to have a look into it. I haven't really done anything substantial with it yet, it looks quite different than inventor, though.

The unconventional way: Antimony

I am living in a box. A box full of boxes. Boxes full of... equations.

Antimony (with its own weird association in my head) lives by the principle of building stuff from mathematically defined primitives. While that may sound strange, it is a logical continuation of the theory behind most volumetric CAD solutions, so it's definitely a thing to look at.

A few years ago, triggered by some guy from the 3D-printing horde, I had a look at OpenSCAD, which works in a similar way and has been around for a long, long time. So, if you can build a tank that way, maybe you can build more sensible stuff, too. I didn't really like working with OpenSCAD, though, mostly because the sources tend to become a holy mess you can get lost in.

Antimony looks different, and in some ways, it works differently - instead of writing endlessly nested sources by hand, you patch them together from boxes of code in a kind of complicated flow chart. That works quite well and is, at a small scale, a lot less of a mess than OpenSCAD, so it's not a bad thing.

Antimony is a work in progress, though. It's still a little rough around the edges. Also, it is still missing a lot of features that could make it a lot more useful - like exports to CAD formats like STEP, exports to 2D vector formats for drawing output, nesting of files (boxes in boxes!)... Also, the stl output is a mess at the moment. There is hope, though - development has been ongoing.

After a little playing around I will have a closer look, if only because I like approaches that are different. There is a lot of potential in the whole approach, thinking of automatic model generation, parametric models and other ideas like that.

That is a rough model of a new etching vessel I want to build for our lab, by the way. As it's supposed to be made from laser cut parts, I will have to do the actual work in a different piece of software, though. Maybe TikZ.

final project -- weekly assignments -- about me -- fab academy