Update on Carrara Dynamic Hair Research

It has been a few weeks since I last updated my progress on my research into Carrara dynamic hair.  With the guidance of PhilW and some other indispensable artists in the DAZ 3D Carrara Discussion forum, I have finally worked out the problems with my long dynamic hair simulation.  The guidance I described in the last article concerning a proxy figure was exactly right.  In brief, dynamic hair in Carrara does not simulate well when colliding with high poly surfaces, such as can be found on most figures.  The result is that the hair bounces and jitters as if it was in a wind tunnel.  The solution is to build a low poly proxy figure that wraps around the figure such that the hair collides with that proxy instead of the figure itself.  PhilW has made such a proxy for V4 that wraps around the whole body, but there is no such proxy for Aiko 3 as of yet.  Thus I had to make one for myself.  In my case, I was more concerned with

finishing my animation than with producing a product, so my proxy is pretty minimal.  I need to work on it before I can release it to the public.

{jumi [*4]}One issue that PhilW brought up was the fact that there seemed to be problems with growing the hair on the actual model, letting the hairs pass through the proxy’s “head,” and then collide with the proxy during simulation.  It just did not work quite right.  He said that growing the hair on the proxy itself produced better results.  This makes sense to me, since that scenario would have the hair poking through an object it was supposed to collide with.  I can see how that might produce unexpected results, but I did not want to grow my hair on the proxy.  It is just not as convenient as growing it on the model itself.  Thankfully, my experiments have found that there is no need to cover the entire scalp with a proxy.  Only the face need be covered.  This allows the hair to grow from the figures head as usual.

My proxy is not a single figure.  I actually made a separate proxy object for each bone in the figure that needed a proxy.  I created one to cover the face, parenting it to the head.  I just used a simple sphere, squashed and sized to cover the face.  I created one to cover the body, parenting it to the chest.  This started as a simple sphere, but I adjusted the shape to conform to the shape of Aiko’s body.  It is too low poly to get a very close fit, but it worked well for my animation.  Last, I created two arm proxy objects.  There is actually only one master vector object that I duplicated and flipped to match the other arm.  Each is parented to the corresponding shoulder.  These started out as cylinders, and I adjusted the shape, size, and position of each loop of vertex edges along the cylinder until it matched the arm well enough.  The trick is to get the proxy far enough away from the body that movement will not result in the figure’s surface poking through the proxy, but to also get the proxy surfaces close enough to the figures surfaces so that the hair is not obviously bouncing off of a force field around the character’s body.

I am still working on an animation to showcase the hair I created and the simulations I am able to run.  Hopefully that will be done within the month.  I hope this is helpful to some of you!