I tried to use Graphics3D today and did not get any ouput (ie, using something simple like Graphics3d[Cuboid[]]); the resource load widget showed that the CPU spun for about 5 seconds but then went flat with no visible change to the Mathematica notebook at all. Other 3D renderings like KnotData[“Trefoil”] worked, although my poor little RPi struggled (CPU running 100% for quite a while). Just curious, is this a known issue? Plotting simple lines also works fine.
Graphics is a fairly troublesome point for this port in its current state and it’s under very active development right now. I think we should be able to deliver some significant improvements on that front relatively soon. Thanks for bringing this particular rendering issue to our attention.
Alex, thanks for your response. Just be clear, I am hopping for joy and with respect for all the hard work the Wolfram and RPi teams are doing to make this a reality! This is so very exciting!
As to the rendering issues, is it possible to output a message to the notebook (screen) saying that something went amiss? I rather have an error message than nothing at all. 
If we find a limitation that affects user experience, we will definitely try to add an error message. The primary goal, however, is to make sure that these rendering errors don’t happen at all.
I’ve done few tests using the remote development panel from a macbook pro and it seems to work nicely, but it could be that in this case part of the work si done by the laptop (e.g the rendering) and it’s not a proper test case.