@jwr
the process to export the board to STEP is just one click…
the only relatively complex part is to prepare the 3D library
to convert board and parts, you need to have a library of 3D STEP format parts (that will be necessary also when the new 3D refactory will be available, you will have to get IGES models instead of STEP)
Basic How To ‘(using kicad StepUp the easiest way)’
(not changing the way you use kicad)
1. just copy the STEP 3d models in the same folder in which there are your wrl 3d models and use the same name of the wrl model name (e.g. r_0603.wrl => r_0603.step)
2. go to your board folder and copy the script kicad_StepUp.FCMacro, the config file ksu-config.cfg and the file ‘launch-kicad_StepUp-demo.bat(sh)’ inside that folder, edit the config file ksu-config.cfg with e.g. notepad changing your model prefix to your KISYS3DMOD path, edit the config file launch-kicad_StepUp-demo.bat(sh) file adjusting FreeCAD path and pcbnew boad file name
3. export from kicad pcbnew the IDF model of the board NB export at Xref=0;Yref=0
4. run the script from command line or from a bash/batch file or with the command:
“path to Freecad executable file”/freecad <kicad_pcb_name.emn> ksu-config.cfg kicad_StepUp.FCMacro
‘(e.g. freecad mypcb.emn ksu-config.cfg kicad_StepUp.FCMacro)’
just watch the script assembly your 3D board with 3D models 
So the process is a bit complex only in configuring the 3D part library, which is not distributed with kicad…
some image of the 3D lib here:
I’m going to add more models to the 3D library I’ve done here, thanks to @Joan_Sparky:
if you go through the repo, you can find 3D models in STEP and VRML for:
chip resistors, chip capacitors, tantalum capacitors, aluminum capacitors, qfn ICs, dip ICs, qfp ICs, soic ICs, sot ICs, ssop ICs, tssop ICs
unfortunately arranging the 3D library is the most complex part in the exporting process… but when you have done it for one board, you have done for all