News about my topic: The problem is that the 3D scenes in PVsyst require OpenGL 2.1 at least, whereas Virtualbox provides support only for OpenGL 1.1 for Windows 10 (actually Windows 8+). I couldn't find any work around. Then I tried to run PVsyst through Wine. Installing Wine, then PVsyst and launching it was not straight forward, but it works! Not perfectly though, as I can't open the Meteonorm database, nor the help documentation and can't edit a report. But the 3D scene works fine and the simulation too. I hope that this would help anyone in the same situation.