Back in the ancient "film" days we used to use various grades of window screening, other metal meshes, or nylon-stocking material inserted in a filter holder to achieve 4-point star effects. Or 8-point if 2 layers were crossed at 45 degree angles. This would also soften the image too much at times and create a much more coarse star pattern. Sometimes that effect was desired. This was before they had "star-filters" which creates much sharper images. If you could find some fine metal mesh that's woven in a hexagonal pattern then you could get your 6-point star effects. You might also have some success by scoring fine parallel lines in clear acetate (transparency material) using a pin. Space the lines about 3-5mm apart at your desired angles. 1 set of parallel lines will spread the light out in 2 directions perpendicular to the lines. Score as many sets of parallel lines for the star-point angles as you want. Some people prefer to use 3 layers and then adjust the star-point angles by rotating the individual layers, much like using polarizers.
