Against the background of inaccurately measured wood particle dimensions, applying the three-dimensional (3-D) image analysis–based particle size characterization system Partimac 3D XL in pre- liminary tests, metal platelets with various aspect ratios of the three main axes are employed to understand and explain the observed limitations of the measuring principle. It was found that particle width and thickness interact increasingly with a decreasing aspect ratio and, thus, the digital replica and subsequent determination of the dimensions become incorrect. This was ascribed to the random orientation of the particles during image acquisition, which cannot be overcome with a finite number of cameras in the system.