Mixing real and virtual elements into one environment often involves creating geometry models of physical objects. Traditional approaches include manual modeling by 3D artists or use of dedicated devices. Both approaches require special skills or special hardware and may be costly. We propose a new method for fast semi-automatic 3D geometry acquisition, based upon unconventional use of motion tracking equipment. The proposed method is intended for quick surface prototyping for virtual, augmented and mixed reality applications where quality of visualization of objects is not required or is of low priority.