Siemens to acquire software maker UGS

German engineering company Siemens agreed to buy software maker UGS Corp. for $3.5 billion, including debt, and separately announced plans to spin off its VDO automotive unit.

Plano, Texas-based UGS, whose software is used by customers including General Motors Corp. to design cars, is owned by Bain Capital, Silver Lake Partners and Warburg Pincus.