NOTE: Unity 5.4 has removed the OpenGL 2.1 pipeline, and the zSpace Unity Plugin has uncovered a bug in the OpenGL 4.5 pipeline, so it does not work with Unity 5.4.
We are working with Unity to resolve the issue, but for now, the zSpace Unity Plugin does not work with Unity 5.4 and above. Please contact us at developer@zspace.com if you are using Unity 5.4