These movies are made with a setup I created for doing particle morphing effects in Houdini. The initial idea for the setup is from Peter Claes’ technical dvd, but it has been greatly expanded to take color and normals into account. It also allows the user to specify attributes to use to blend between color/motion/normals (such as distance to target, age of particle, length of time in group, etc), which are hooked up to ramps for a great deal of control. I may post a screen capture of how the OTL works soon.
Houdini Particle Morph Example