This Trimming a Path through LightWave 3D Fiber FX Tutorial uses a relatively simple technique of animating an alpha channel over a texture map to animate cutting or trimming a path through FiberFX. This is only one of many different ways to animate trimming a path, but it is a quick and easy method using a simple grayscale UV texture map and an alpha channel controlled by an animated null.

This simple technique can be used to animate trimming a wide variety of paths such as cutting a path through grass with a lawn mower, giving a haircut or trimming a path through a beard with a razor as was used in this particular project.

http://dreamlight.com/trimming-a-pat...r-fx-tutorial/