1. A method of generating a control signal of a computing system having a touch sensitive surface, the method comprising: obtaining motion information of a plurality of contacts, the contacts corresponding to touch devices on or near the surface at the same time, the motion information including a first value of a first component of motion that is one of translation motion, rotational motion, and scaling motion, and a second value of a second component of motion that is a different one of translation motion, rotational motion, and scaling motion than the first component of motion; determining an input activity; modifying the motion information to obtain modified motion information, the modifying including downscaling the second value with respect to the first value; and generating a control signal of the input activity based on the modified motion information.