The technology disclosed relates to initializing orientation of a three-dimensional (3D) model of an object. In particular, it relates to accessing at least one three-dimensional (3D) model of an object and observed information of the object movable in space and determining a primary orientation parameter of the model from the observed information. The method further includes detecting contours of the object in the observed information and calculating a representative normal to the detected contours, accessing a vector representing a 3D angle from the object to a point of observation, calculating a primary orientation of the object as a cross-product of the representative normal and the vector, and using the calculated primary orientation parameter to initialize the model.