Stiffness and damping

now that you are comfortable with how Springs expand and contract we can try something a little bit different let's try connecting a bunch of Springs together like this when we simulate Springs we don't draw them using the zig zag pattern instead we use lines which can expand and contract this gives us a really bouncy strand of hair but it's a bit too bouncy notice the hairs take a really long time to settle down this isn't very realistic take a look at a reference shots again see how quickly the hairs come to rest just a few bounces you might think changing the spring stiffness will fix this but look what happens both low and high stiffness values still result in hair which never settles down our solution to this is adding what's called a damper to each spring a damper is something that resists fast changes in displacement and it's used to bring Springs to rest much more quickly check this out here we have the same strand of hair as before except each spring is connected to a damper and we can change the amount of damping using this new parameter if we increase stamping the springs resist quick changes and therefore come to rest much faster however too much damping will result in really stiff hair which isn't natural and here is what it looks like with a whole bunch of hair we went through a similar exercise in early stages of modeling Merida's hair we were trying to get the right mixture of spring stiffnesses and damping so that we could achieve the desired artistic look but with the wrong settings the spring start fighting each other and you get pretty funny results so the trick is to find a nice balance between spring stiffness and damping you can try this out in the next exercise here you can control damping of each spring number of hairs number of Springs for hair and spring stiffness see if you can come up with something that behaves a bit more realistically