This project serves as template for an altium raspberry pi and/or arduino project. The shield is a combination of an arduino shield and a raspberry pi 3 shield. The template is based on my raspberry pi project (https://github.com/NilsMinor/Raspberry-Pi-3-Altium-Template) and the uno template from (https://forum.arduino.cc/index.php?topic=115446.0). You can start your project from the main schematic sheet. There is a pictrue below as reference. The shield supports mounting holes for both boards, arduino and raspberry pi.
However I can not ensure the correctness of the design, since it was not produced in the moment (but will be built in the future). Use it as it is without any guarantee. If you find a mistake please let me know it :)
For more informations : http://nilsminor.de/index.php/2018/03/04/altium-template-for-a-combined-arduino-and-raspberry-pi-shield/
kindly