In October (2012) I started a workshop to learn the basics of Houdini.
In the fifth week we looked deeper into particle manipulation to create some cool simple effects. One of these was a dissolving effect. We received an animated mesh and had to make it seem like it dissolved into a cloud of particles. The setup is as followed:
First was making the mesh disappear. This was done by applying a color to it with noise. Black stayed, white gets deleted. Because the mesh moves, and thus would move through the space of the noise, a Timeshift is applied to keep the mesh at frame one. With a Solver, the color value gets added up, so it gets brighter and brighter. These color values then get transferred onto the moving mesh. Once the value of R (Rgb) goes above 0.95, it gets deleted. Then a Group and another Delete gets applied by using the R value. This results in the edge of the remaining mesh, on which points are scattered.
To have particles emit from the inside, a similar kind of setup (using the R value) is used by scattering points in a volume and transferring the R from the mesh to those points. The remaining points from the volume get merged with the ones from the mesh and this used to emit particles from.
To finish off, the applied color gets deleted from the mesh to get the original back.
This was one of two effects we did that week. You can view the other effect here: vimeo.com/56101872