A Houdini setup based on the Aaron Hertzmann’s
paper on painterly rendering
Using COPs and vex in Houdini I recreated Hertzmann’s painting algorithm.
The input image is blurred and points are trailed along the image’s
gradient (calculated in vops); stopping when the colour change in the
blurred image passes a threshold. Layers of these trails with different
thresholds and blur sizes creates the final image.