Improbable, the London startup that has developed a platform for third parties to build vast virtual and simulated worlds, has landed a stratospheric round of funding to double down on its product and expand its ecosystem of developers. The company, which also has offices in San Francisco, has raised $502 million in funding led by SoftBank, with previous investors Andreessen Horowitz and Horizons Ventures also participating.

The company is not disclosing its valuation but Herman Narula, the CEO and co-founder, told TechCrunch in an interview that it’s a minority stake. The company had only raised $50 million prior to this, placing the valuation at around or over $1 billion.

Rumors of this round were making the rounds, so to speak, some weeks ago, with little detail on the numbers.

The SoftBank investment, Narula told me, is not coming from the new Vision fund — the $100 billion or so superfund that includes the likes of Apple as partners — which has yet to be officially announced. It could “move into that” in the future, he added.

It’s a huge leap for the company — one that you could nearly say befits its name, when you consider that the company has had relatively little buzz compared to others in the adjacent areas of virtual and augmented reality.

“It’s the right time,” said Narula. “We’ve reached the point as a company where we have demonstrated the core solutions and now is the time to double down on the ecosystem and technology.”

Improbable made its name with its platform called SpatialOS. Launched last year, it lets developers design and build massively detailed environments by using distributed cloud computing infrastructure, incorporating machine learning technology and other advances.

Alongside platforms like Google VR and Unreal Engine, it gives developers a springboard into creating immersive experiences, which many believe will be the future of how we will interact with many services — both leisurely and utilitarian ones — in the future.

“Our goal is to build a massive scale infrastructure to redefine how we work on a massive scale,” Narula said.

So far some of the most immediate applications for SpatialOS have been in gaming — for example the multiplayer game Worlds Adrift was built on it. Narula believes gaming will continue to be a big area: he said that the company has “not yet” worked with gaming phenomenon Supercell, but he hopes the SoftBank connection will help broker a relationship there.

Indeed, the SoftBank connection is not just financial but potentially opens the door to a number of other businesses in other verticals like transportation — where next-generation mapping and autonomous driving are the names of the tech game. You can see how Improbable market opportunity could prove to be as big as the the worlds it hopes to help build.

As part of this round, SoftBank managing director Deep Nishar is taking a seat on Improbable’s board.

“Improbable is building breakthrough technologies that are becoming vital and valuable platforms for the global gaming industry,” he said. “Beyond gaming, this new form of simulation on a massive scale has the potential to help us make better decisions about the world we live in.”