Recent research has shown that machine strength grading based on tracheid effect scanning of fibre directions projected on board surfaces can provide more accurate strength predictions than today's grading methods. Scanning techniques in which 3D fibre orientations can be taken into account would most likely improve the strength grading results even further. In this investigation the possibility of determining such 3D orientations by dot laser scanning was investigated. For a set of 20 side boards, scanning data was used to calculate traversing knot directions which were in turn applied to determine pith location and root end of original logs. By means of the shape of laser dots, which due to the tracheid effect are turned elliptic on board surfaces, and the determined pith location, the size and direction of the diving angle of the fibres was calculated. The research showed that this angle can be accurately determined in the vicinity of knots.