When Google announced Daydream during their annual I/O keynote on Tuesday, the company announced they were working with two big third-party game studios, Electronic Arts and Ubisoft, to make games for the new platform.

Yesterday they added a third name to the list: Epic Games. Epic's powerful game engine, Unreal Engine 4, will be coming to Daydream, ensuring developers can easily port their existing apps to the VR platform without too much work.

This plugin comes from a collaboration between Epic, Google and Hardsuit labs.

More importantly, from today applications in Unreal Engine 4 will also join the Google Cardboard app library. If you're running an app and it's not on a Daydream qualified device, it'll drop back to "Cardboard-level support".

This is great news for the hundreds of thousands of Cardboard-ready devices that aren't quite ready for Daydream, and that audience isn't likely to away any time soon, with Daydream-certified devices bound to be outnumbered by their lower specification cousins for a long while.

This is also means people can develop for Cardboard, which is a big step forwards for the free headset. You can pick up the UE4 plugin from Github now.