Yeah, I found that out the hard way. Even though the chat support from Nvidia said I did not need it, they were wrong. I found one place on the entire web that had it in stock, and once installed, we could use Maestro to see 3D structures. I wish the information on the Nvidia 3D vision(pro) site would make this clear. Having a little number icon that says 'optional' is just not right and it should say on windows its optional but on Linux its Necessary. I blame Nvidia's poor customer support and lack of proper documentation on this issue.