I had issues with piplay to find my device with gtx1070 and Win7/64.
And solution was Oculus driver ( oculus_runtime_sdk_0.8.0.0_win.exe) installation.
Oculus detected Pimax. Then I did uninstall Oculus and reboot pc.
Next I did install PiPlay again, and there it was, after several tricks, Pimax detected.
Somehow these oculus drivers did something right, to help piplay to detect pimax.