Content creation for computer graphics applications is a very time-consuming process that requires skilled personnel. Many people find the manipulation of 3D object with 2D input devices non-intuitive and difficult. We present a system, which restricts the motion of objects in a 3D scene with constraints. In this publication we discuss an experiment that compares two different 3D manipulation interfaces via 2D input devices. The results show clearly that the new constraint-based interface performs significantly better than previous work.