Recently, considerable research has been carried out regarding three-dimensional object manipulation on multi-touch surfaces. However, most current solutions were developed having in mind scenarios with a camera perpendicular to a scene axis, and cannot be easily used to manipulate three-dimensional objects in unconstrained viewpoints. In this paper, we present and evaluate a set of object manipulation techniques. As a test bed for this study, we used an unconstrained virtual LEGO modeling tool, taking advantage of ongoing work and popularity of LEGO construction among people of all ages. From this evaluation we improved our understanding on how users prefer to manipulate 3D objects on multi-touch surfaces.