To register 3D meshes representing smooth surfaces we track the 3D digitization system using photogrammetric techniques and calibrations. We present an example by digitizing a 800mm×600mm portion of a car door. To increase the tracking accuracy the 3D scanner is placed in a cubic frame of side 0.5m covered with 78 targets. The target frame moves in a volume that is approximately 1100mm×850mm×900mm, to digitize the area of interest. Using four cameras this target frame is tracked with of an accuracy of 0.03mm spatially and 0.180mrad angularly. A registration accuracy between 0.1mm and 2mm is reached. This method can be used for the registration of meshes representing featureless surfaces.