This is an old project of an advanced foliage spawning tool that I created using construction script to quickly place foliage in complex shapes. With this tool, the artist can control the density, variety of foliage they want to place, randomness in position, scale, and offset. This is based on the theory I found on this link:
https://stackoverflow.com/questions/217578/how-can-i-determine-whether-a-2d-point-is-within-a-polygon