[1] http://cdn0.vox-cdn.com/assets/4490157/1-main.pdf
[2] http://www.theverge.com/2014/5/21/5739086/oculus-vr-and-its-...
[1] http://cdn0.vox-cdn.com/assets/4490157/1-main.pdf
[2] http://www.theverge.com/2014/5/21/5739086/oculus-vr-and-its-...
Edit: Clarified "this lawsuit" and "side effects in any competitors".
The whole piece reads as if ZeniMax felt that it has somehow acquired possession of Carmack's knowledge (or any other of its employees), which at least for me seems to be totally absurd.
Carmack obviously re-wrote all code once leaving Zenimax, but there's a case to be made that Zenimax giving Carmack free reign to work on Oculus while at Zenimax significantly benefited Oculus.
Oculus agreed at some point — offering Zenimax a 2% stake. Zenimax asked for more (amount not specified in the complaint). Oculus response was that the "figure was so far out of the ballpark, we believe there is little hope" — negotiations broke down there.