Fixinspect PG is a range of specially coded measuring accessories in the shape of cubes, which serve to mark and locate bores, edges and corners in support of “picture measuring” or photogrametry. In photogrametry, an object first surveyed 2-dimensionally from different directions so that all relevant areas of the object are documented. The digital “measuring” pictures are processed and 3D co-ordinates of relevant geometric points are calculated. However, hidden or hard to reach areas can be invisible to a camera. Mounting Fixinspect PG cubes on the workpiece to be measured makes them visible. The cubes (30 by 30 by 30 mm) are equipped with differently arranged coded markings/points which allow accurate definition of features. Underneath, the cubes are equipped with exchangeable fixing pins or magnets in different sizes, which are used to mount them on workpieces. With different types of cubes, even difficult-to-access areas can be documented accurately. The range available includes special accessories for 90° inner and outer corners.