A method for obtaining a refined pose for a 3D sensor for online 3D modeling of a surface geometry of an object, the pose encompassing six degrees of freedom (DOF) including three translation parameters and three orientation parameters, the method comprising: providing the 3D sensor, the 3D sensor being adapted to capture 3D point measurements of the surface of the object from a viewpoint; providing a geometry model of at least part of the surface; observing a portion of the surface of the object with the 3D sensor; measuring an initialization pose for the 3D sensor by at least one of positioning device pose measurement, predicted pose tracking and target observation; finding a best fit arrangement of the 3D point measurements in the geometry model using the initialization pose; generating the refined pose for the 3D sensor using the best fit arrangement.