Unity Technologies, which provides a platform for developers to create high-quality 3D games, said that the company has now registered more than 750,000 developers. About one-quarter, or 200,000 of them, are active on a monthly basis and more than 250,000 developers have signed  up in the last six months.

Unity provides tools that help gaming companies get around technology issues like rendering, creating terrain and managing lighting in very high-end games. The company has raised $17.5 million to date from investors including Sequoia Capital.

Unity says growth is coming from a content marketplace and a new game distribution service the company launched a year ago. The marketplace helps gaming companies sell art assets like animations or objects like 3D barrels that can be strewn about strategy or first-person shooter games. Unity splits the proceeds 70-30 with developers and the store has 50,000 registered developers with 2,200 packages there. The top vendors there are making about $10,000 per month, up from about a $2,500 rate a year ago. Its distribution service, called Union, doesn’t have very many details about where these games are sold or their conversion rate. However, the company says developers keep 80 percent of the proceeds from a sale.