Flow Engineering, a startup that offers AI tools for hardware design, has raised a $50 million Series B round at a $750 million valuation from some big-name investors, the company announced on Wednesday.

The round was co-led by Antonio Gracias of Valar Equity Partners (best known for its investments in Elon Musk’s companies, particularly SpaceX) and Gavin Baker of Atreides Management (a hedge fund that has also backed Musk’s companies and others like AI chipmaker Cerebras). Sequoia Capital, which led Flow’s Series A round last October, also participated, as did former Sequoia partner Roelof Botha, who invested as an individual investor. Botha has joined Flow’s board, too.

Three-year-old, San Francisco-based Flow is is tackling the difficulties of hardware design by offering AI agents that automatically align CAD drawings with product requirements, simulation results, and other testing.

It names Anduril, Rivian, Joby Aviation, General Motors PPU (a joint venture between General Motors and TWG Motorsports), RV Tech (a Rivian and Volkswagen’s joint venture), Stoke Space, and others, as customers.