KiCad Custom Parts

I guess everyone using EDA software knows this: You're designing a board and the software is missing your part completely or the footprint or the 3d model. I had pretty much all of the above for different parts. And since I usually like to learn how everything works, I spent a bit of time to create schematic parts, footprints and 3d models.

Adding a schematics part in KiCad actually is really easy and quickly done - although I'd wished there were some shortcuts. Or maybe I just haven't found them. For example, if you notice that you set most of the pins to the wrong pin type. I would assume (from other software experience) that you can just select all pins, open a properties window and set just the type to the correct one for all parts at the same time without changing any other value. This even works for mp3 metadata editing in most freeware tools... But sadly not in KiCad. So you have to select each pin and update the pin type field for each one individually. And yes, I know it's open source and I could just fix it and submit a pull request to the devs. But right now I am trying to work on the project and I already have too much on my plate anyways...

Next up is the footprint. And again, I tip my hat to the devs, it's really easy to learn, a very usable and helpful ui. So this was done in pretty much no time at all.

Finally the 3d model. And this is sadly where it got really frustrating. The 3d modelling software i am working with cannot export .step or .wrl. So I had to install a few recommended tools to convert everything to the right format. And here I got the full load of problems when converting mesh data. This of course is not the fault of the KiCad devs - it's a systemic problem with lots of different and usually badly incompatible formats and versions and feature sets that really stops you doing what you want to do. Spoiler alert: In the end I managed to get 2 meshes working (mostly) correct in KiCad (a relay and a screw terminal).

In essence, my workflow is the following: Build the meshes in my 3d modeller (remembering that y and z are swapped), export all meshes from my 3d modeller in Wavefront obj format (each material as one file), import the meshes into FreeCAD (with the kicad stepup plugin), convert the meshes into solids, set proper materials for the solids, select all solids and hit the export button. All in all, it's very tedious and full of pitfalls and chances to make small mistakes... I guess the best option for me would be to write a custom step/wrl exporter for my 3d modeller. Should be doable - if and when I find the time for it...

In summary:

KiCad is a nice tool and you can very easily (with minor ui failings) add custom parts and footprints. But I would strongly discourage anyone to try to add 3d models as well. In my ipinion it's not worth the time and energy just to get a pretty 3d rendering of your board. Just ignore the missing models. It's good enough to get a good feel for the layout and size of the board - even with some parts missing. If however you're using a 3d modelling software that can directly export step/wrl it's a different story...

shamada