After being threatened with legal action by id Software parent company ZeniMax, virtual reality frontrunner Oculus says it hasn't taken so much as a line of code from the company. Last week, ZeniMax said that the Oculus Rift VR headset couldn't have existed without help from John Carmack, who it accuses of giving Oculus intellectual property developed at and owned by ZeniMax. Carmack, who co-founded id but left to work at Oculus last year, was an early supporter of Oculus, and Oculus has previously acknowledged his support. But it says that ZeniMax played no part in the process and actually impeded VR development.

"There is not a line of ZeniMax code or any of its technology in any Oculus products," says Oculus in a statement, and Carmack "did not take any intellectual property from ZeniMax." Instead, the company accuses ZeniMax of making misleading and vague claims. ZeniMax has cited a non-disclosure agreement that Oculus founder Palmer Luckey signed in 2012, in which it bars Luckey from using or claiming ownership of unspecified VR software. According to Oculus, ZeniMax "has misstated the purposes and language" of the document and has "never identified any ‘stolen' code or technology" in the company's publicly available source code.

The company also refutes allegations that ZeniMax had attempted to get compensation for stolen intellectual property well before Facebook bought Oculus for $2 billion last month. "Zenimax did not pursue claims against Oculus for IP or technology," it says, "and only after the Facebook deal was announced has Zenimax now made these claims through its lawyers." It also points out that Carmack has previously said he left id because ZeniMax wasn't interested in VR development.

One of the most interesting claims, though, is that a financial spat with ZeniMax is the reason that Doom 3 BFG never ended up supporting VR. Doom 3 was one of the first games tested with the Rift, and it was supposed to be one of the very first games released for it — every development kit, in fact, was supposed to come with a copy. That plan was later scrapped. ZeniMax claims that it previously attempted to settle with Oculus over intellectual property, asking for equity in the company. Though Oculus maintains that there were no intellectual property disputes involved, it confirms that some kind of negotiation happened, saying that ZeniMax canceled VR support for Doom 3 when Oculus refused to grant it equity. Since the legal threat was made public, Oculus has characterized ZeniMax's claims as the standard fee-chasing that companies see during an acquisition. "We are disappointed but not surprised by ZeniMax's actions and we will prove that all of its claims are false," it says.