Simulation - Animating with Blender: How to Create Short Animations from Start to Finish - page 283

Hair

Applying the Soft Body simulator to strand-based hair allows it to bounce and move realistically with the
character's animation. In my own experiments, simulation times with collision enabled once you near or pass
a thousand strand parents becomes a little too high for the feature to be useful. The problem isn't the fi nal
round of calculations before the rendering, but the diffi culty in tweaking and tuning such a system. Five min-
utes to bake a 50 frame simulation is certainly usable, but only if you have an entire day to devote to running
the simulation 30 or 40 times while you try to get it right.

If your characters have long hair that is going to be whipping in the wind, fl owing, and trying to wrap itself
around both the character and its surroundings, you will have to use the collision feature, which will really
slow you down. Using collisions in the simulation and enabling the character's mesh as a defl ector object will
keep the hair on the outside of the character, where it belongs. We'll look at that in a moment.

Fortunately, you can use the Soft Body simulator to give your character's hair and fur enough bounce to
really come alive without the need for collision. In the real world, most peoples' hair actually stays relatively
in place except under extreme conditions. Since we are just going for some nice secondary motion that will
add believability to a shot, this should be quite good enough.

With a fi nished hair system, like the mother's in Figure 14.83, select that system in the Soft Body panel of the
Physics buttons before enabling the simulation. The pop-up menu to the right of the Soft Body button con-
tains entries for the object itself and any particle systems the object may have. In this way, you can enable a separate
soft body simulation for each of them if you wish. The panel shown in Figure 14.84 shows the settings that pro-
duce a small amount of secondary motion for the mother's hair without collisions or exorbitant calculation time.

Figure 14.83 The mother's hair system Figure 14.84 Settings for a small amount of soft body motion

WARNING
Failure to select the particle system in the Soft Body panel will result in a soft body simulation
being applied to the emitter mesh!