Paint brush

For this paint node I spawn triangle instances wherever the artist paints, always storing the last brush stroke position and comparing that to the current mouse position, calculating how many triangles, if any, should be linearly spaced in between the two points, based on the parameters for brush spacing and size. With those two data points I also calculate a direction vector, so that artists can paint with a texture as a brush stroke and align that brush in the direction they are painting. Motif supports wacom tablets, so I was able to query the pressure of the pen stroke and multiply the scale and opacity of the brush stroke accordingly.