ZeniMax Media, the parent company of both Bethesda Softworks and Id Software, has sent legal letters to Oculus and its new parent Facebook alleging that storied Doom programmer John Carmack aided in the development and creation of Oculus Rift technology while he was still with ZeniMax, giving the company claim to at least part of the headset's intellectual property.

As reported this morning by the Wall Street Journal, ZeniMax alleges that technology Carmack developed while he was still at ZeniMax was the genesis of what would eventually become the Oculus Rift development kit. ZeniMax traces this technological relationship back to E3 2012, where Carmack showed a very early "ski goggle" Rift prototype at the ZeniMax booth to great acclaim from industry and press.

ZeniMax has been seeking compensation for that early contribution to the Oculus tech since August of 2012, according to unnamed "people familiar with the discussions" cited by the Journal. Negotiations reportedly went on for six months and included the possibility of a ZeniMax equity stake in Oculus, but they ended without a deal. Carmack later took on a new role as chief technology officer at Oculus and formally departed Id and ZeniMax a few months after that. Oculus was acquired by Facebook in a $2 billion deal earlier this year.

"It's unfortunate, but when there's this type of transaction, people come out of the woodwork with ridiculous and absurd claims," an Oculus spokesperson told Ars Technica. "We intend to vigorously defend Oculus and its investors to the fullest extent."

A ZeniMax Media spokesperson was not immediately available for comment, but in a statement to the Journal, ZeniMax said it had "sent formal notice of its legal rights... and will take the necessary action to protect its interests," indicating that a lawsuit is an option.

Carmack’s early Oculus work

Oculus employees have frequently cited Carmack's early support and promotion of the Rift as key to the company's success and ability to attract attention from others in the industry. What's less clear is just how much of Carmack's technological knowhow went into the Rift while he was still a ZeniMax employee and what legal claim the company has to his technological contributions.

Carmack famously stumbled on the existence of the Rift when trawling 3D headset forums while doing his own head-mounted display tinkering, at which point Oculus cofounder Palmer Luckey sent the Doom developer an early prototype of the headset to test out and demonstrate. Carmack went into more detail about his role (or lack thereof) in further Oculus hardware development during a lengthy QuakeCon 2012 keynote presentation alongside Luckey and Valve's Michael Abrash.

"I was heading down almost the same route on there. I was cobbling some things together myself," Carmack said at the time. "I ran into Palmer [Luckey] and he had basically built something probably better than something I would have done if I had put it together myself. So I'm like, OK, I can abandon work on all of these projects and this is the platform."

"Mostly as a software guy, I want something to write software for," he continued. "It's fun to tinker with the hardware, but I'd really just as soon have someone else do that. It's only in cases where I can't see someone else doing the right thing that I find the need to make something happen myself."

In a G4 interview at E3 2012, Carmack referred to what he called his "research and development work on virtual reality headsets" in connection to the Rift. But in a PC Gamer interview at the same show, Carmack described his interest in head-mounted displays as "my toy project—it really wasn't a sanctioned company endeavor [because] it's not at all clear how Id Software and ZeniMax monetize a head-mounted display."

Carmack did develop a new version of Doom 3: BFG Edition that was used to demonstrate the Rift prototypes at its first few trade shows. That game was originally planned to be packaged with every Oculus development kit, and it seems likely that these newly surfacing disagreements over rights to the technology may have gotten in the way of that bundling.

Both Carmack and ZeniMax Media got a "special thanks" in Oculus' initial Kickstarter pitch.

[Update: Carmack has tweeted a brief response to these allegations, saying, "No work I have ever done has been patented. ZeniMax owns the code that I wrote, but they don't own VR."]