Mastering Hair Physics: Tips & Tricks for Smoothly Simulating Hair Movement

[papillon68]

Hi, I'd like to ask some help and suggestions about simulating hair physics (so basically pulling hair vertices around, and smoothly disposing the adjacent ones).

Please take a look at the embedded video (which shows an application tha can do it): the hair displayed there is made of 15 vertices; once the user drags the active vertices (those inside the circular cursor area), all the hair vertices are moved and repositioned accordingly. To notice that hair length remain the same during the process.

Thanks for any help.



https://www.youtube.com/watch?v=lW4sa_vXBRg

 

[papillon68]

Sorry, I had troubles embedding the YT movie, now it's there.

 

[Nanako]

suggestions. you're going to need to model whatever it is that makes the hair stand up on end again, after being pushed down. elasticity? stiffness? i don't know what it's called. but generally, your video shows hair behaving like a string of dough, which doesn't seem authentic. usually if you push the middle of a hair to the side, the top will bend with it, and the whole thing will just bend at the point of contact. of course that depends on how long it is.

 

[256bits]

It basically looks like a Bezier manipulation of a line to adjust the curves. Try out any program that has Bezier curve shaping, and you will see the same effect, although the length of the line or hair would not stay the same in most programs.

Whether or not a hair will behave like that, is beyond my knowledge of the physics of hair. But if a hair is being manipulated in a viscous fluid or gel, one would think something similar would occur, depending on the viscosity of course.