Trimble Navigation Ltd has agreed to buy SketchUp 3D modeling platform from Google Inc for an undisclosed price, the companies said. As part of the SketchUp platform, Trimble will partner Google in developing SketchUp’s 3D Warehouse - an online repository where users can find, share, store and collaborate on 3D models, the companies said in a joint statement. Trimble, which makes surveying, mapping, and marine navigation equipment, said SketchUp will enhance the integration of its field presence with the wider enterprise. SketchUp is a free 3D modeling platform that helps in designing 3D models within Google Earth - a virtual map of most of the planet’s surface. The platform enables users to create collections of models, including 3D buildings, and share them with fellow modelers around the world. SketchUp, which was a tiny startup when it was bought by Google in 2006, now boasts of millions of active users. “With over 30 million SketchUp activations in just the last year, we’re awfully proud of our accomplishments,” John Bacus, SketchUp product manager wrote in a blog post. The deal is expected to close in the second quarter of 2012, and it would not be material to Trimble’s 2012 earnings. Trimble’s stock was trading flat at $53.98 in morning trade on the Nasdaq on Thursday.