Archive for FreeCAD

Tutorial: Custom 3D models for KiCad 3D viewer

Posted in Tutorials with tags , , , , , , , , , , , on March 30, 2014 by sethkoberg

One of my favorite features of KiCad is the built in 3D viewer functionality. A lot of your standard components will have a 3D model already assigned to a module, like resistors, capacitors, IC’s, etc., so when you fire up the 3D viewer, you will get a nice approximation as to what your finished, populated PCB will look like. In the image below, all the components came bundled with KiCAD, with the exception of the USB connector. When it comes to modules you’ve download from the web or have created yourself, you may have to create a custom 3D model for that module.

Case in point, my FT230X breakout board uses a Mini USB-B connector which I needed to create a schematic component and PCB module for. Clearly, creating these files didn’t magically generate a 3D model for viewing in the 3D viewer.

Rendered 3D model of my FT230X from KiCads 3Dviewer

Rendered 3D model of my FT230X from KiCads 3Dviewer

Requirements:

  1. 3D modeling software – I used Wings3D for this project to import an OBJ file to edit and export to VRML (*.wrl) for KiCad. You can use any 3D modeling software you like – another good, free one is Blender3D. Whichever modeling software you choose, make sure you know the basics so you can clean up the model you’re modifying. Also, this extra piece of software is needed because the VRML export doesn’t work from FreeCAD, so we need a middle man to take care of that.
  2. CAD software- I’m using FreeCAD to export CAD files to OBJ to modify in Wings3D (you didn’t think I was going to make you actually model anything, did you?). You can use this software to modify the CAD model before exporting to the OBJ format, but since I’m only using it to convert the files, I’m not bothering with learning another piece of software this week.
  3. 3D CAD drawings of your component – You can find these on the manufacturer websites for the part your creating. For this USB connector, searching the part number (67503-1020) on the Molex website will lead you to a link to download 3D CAD Models – they’ve already done the hard work, so why should you.

Downloading CAD Models

For this USB connector, Molex has provided 3 formats for the CAD model: PRO/E, IGES, and STEP. The manufacturer may offer more or fewer formats for the component you’re working with, but a cursory glance at the capabilities of FreeCAD suggests most standard file formats should work. If the manufacturer hasn’t supplied a file format that can be imported into FreeCAD or doesn’t supply 3D CAD models, you may need to find a similar component from a different manufacturer that does for the purpose of this tutorial – you don’t need to use the secondary component in your project and rework your schematic and PCB, as this is just for a 3D rendering, not the final product.

Download the 3D Model file from the manufacturers website and save the file, typically a *.zip, to your computer, then extract the file from the archive to a location that makes sense – I extracted my file to the project directory for the FT230X breakout board.

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