I have installed the GMH2.6 plugin and tried to follow the developer’s PDF tutorials. Nevertheless, it is very confusing and I find it very bad explained and unorganized. I tried to find video tutorial of the usage of this script but I couldn’t find any and there aren’t any reference on internet of how to proceed. In my process I get stuck in the baking of the maps. I had to do a lot of testing in order to understand how the properties work and to keep the hair inside the plane.
The process of baking the hair with this plugin is creating a plane per each type of lock you want to use. Then apply a different GMHHair system to each plane and tweak the properties to get the desired result. One important property to modify is the flatness and cross section number of polygons as will determine the tridimensional volume of each hair string. Also important are the two different curves of density decay that determines the length and the width of the Hair strip. It is important to fit the hair inside the baking plane. Then to modify the hair shape the most important property I found was the noise and the noise frequency. There were also options to make wavy and curly hair but since my model was going to use straight hair I didn’t try them too much. Once I had the desired hair shape, I selected them, check the autoUV box and create UVSheet of the selected surfaces. After that Select the size of the maps and the type I wanted between lit and shaded, diffuse, normal, alpha and displacement and bake the maps. In order to create the normal map without errors was necessary to move the hair using the oddset property in such manner that any hair strand do not cut the plane surface, if not it will create yellow surfaces on the map.
The process take like 10-15 min per map to finish so each test to change the maps take a lot of time. More even if you do the postprocess retouch adviced in the PDF’s tutorial, where you have to open the planes in Photoshop, combine some of them or using filters and grey scale value tool in order to get the final result. In my case I have repeated the process several times due to errors in the strips of hair where some of the strings where out of the baking surface and were cuts in the texture.
I have also tried to follow a tutorial that talks about an older version of this plugin. Never the less the interesting part was the recommendation of usage of a Zbrush brush in order to create polygroups strips along a surface. I downloaded the brush and used it to create a series of strips using the surface of the ponytail base. The result was great and very easy to use and tweak. But back to Maya I did not understand the next step in the process of hair creation of the plugin and I get stuck without knowing how to continue.