Start, Rest, and Current Position curves

There are three sets of curves for the hair system.

Start Position

This is the position of the hair at the start frame of the simulation. When first created, the Start curves stick straight out from the surface.

Rest Position

This is the position of the hair when no forces (such as gravity) are acting upon it. You can use these curves to influence the shape of the hair.

Working with Rest curves is like styling hair with hairspray. The Rest curves are styled into curls and flips, etc. When the simulation is played back, the hair adheres to the Rest curves position as much as possible depending on dynamic forces and attribute settings in the hair system and follicles. For example, if your hair is not very stiff and you’re simulating a windy day, the hairspray (Rest curves position) is less likely to hold the hair in position.

Tip: The Damp value can be used to relax oscillating curves on non-straight hair.

Current Position

These are the output and/or Paint Effects curves generated by the hair system.

This is how the hair behaves when you play the simulation, which includes built-in dynamics. Do not edit the Current Position; just view it.

The Stiffness and Iterations attributes in the Hair system’s Dynamics section are what control the tolerance of the Current Position achieving the Rest Position.