I worked very hard with many iterations to get this octocopter fly perfectly. It has been developed to be very easy to fix. All the arms are the same, so if you break one, just print it. Note : You need to print 4 times these files : DRONE_EVIDE2.stl and PIED.stl You can find all info on the website : www.octo3D.thomaero.fr And please download the build PDF with images, PID etc. https://www.dropbox.com/s/0ne7500dldfyijz/Manuel%20OCTO.pdf?dl=0 Feel free to contact me to get original CAD file (CATIA) and ESPECIALLY feel free to modify it in a better way.