Microsoft has bought Caligari, the developer of 3D modelling software trueSpace, in a move that could help enrich the graphics experience in Microsoft's Virtual Earth mapping system.

Caligari started making 3D modeling and animation software for the Amiga computer in the mid-1980s. Its signature tool, trueSpace, has a user interface that makes it easy to build complex 3D animations, according to an entry on the Virtual Earth blog on Wednesday announcing the acquisition.

Caligari has offices in Mountain View, California, and Slovakia. Its development team will work with the Virtual Earth group, and Caligari's "tightly knit community of beta testers" will stay the same, said Roman Ormandy, founder and CEO of Caligari, in a blog posting. He said the company will become a wholly owned subsidiary of Microsoft.

"Now we will have more resources to rely on, larger market to consider and I hope more fun doing that," he wrote.

Microsoft was not available for additional comment.

In December, Microsoft bought Multimap, which also became a wholly owned subsidiary and works with the Virtual Earth and Search groups. Multimap develops online mapping services. At the time of that acquisition, Microsoft said the buy would help it expand its online services offerings to consumers and businesses.

Virtual Earth's 3D version, currently in beta, lets users zoom in and out of 3D maps of cities and natural areas. It is similar to Google's Google Earth product.