Introduction
In this tutorial, I'm going to show you how to make short
human hair using Sasquatch's fur mode. The character I'm using here
is from my ongoing project, Brad Pitt. I've seen many women characters
done with Sasquatch's long hair mode, so I picked a man with short hair
to be different. My method is versatile so it's applicable to fur or
grass once you understand the basic approach. I hope you get a chance
to experiment with this technique yourself.
Step 1: R & D
Brad Pitt has always appeared on screen with different
hairstyles, but for reference I used the style from my favorite Pitt
movie: Fight Club.
You can picture what his hairstyle is like... your hair becomes greasy
after having no chance to take a shower for a few days. You really need
to think and imagine the style in order to recreate it! But it’s
harder to make specific looks on purpose than I imagined it would be.
The lighting method that the director Fincher uses in his movies is
almost always dark, with a lot of key lights from the sides so his dark-brown
hair looks black. Despite the conditions, the hair still looks rich
because the specular highlights enhance the qualities and the outlines
of the hair.
I won't tell you which particular scene I used as a reference. You can
watch the DVD or the video and see if you can find the scene yourself.
Step 2 Mapping
Almost all Sasquatch 1.5 parameters can be textured in Sasquatch's "S" panels and Sasquatch 1.5 also supports vertex weightmaps. I used no image maps at all; just weight maps for everything. With normal maps, you can load them as basic coordinates like Planar, Cylindrical, Spherical, and UVMap, but since Sasquatch doesn’t allow multiple layers of maps per attribute, precise adjustments are sometimes tricky. Even if you use the useful Unwrap tool to make a Cylindrical map, it’s hard to paint the place you aimed at, especially on the seams. But with weight maps you can paint on the 3D objects directly in Modeler, so it gives you a lot more controls It’s really fast and convenient!
(fig
1) Set up where you want to grow hair on the head using a Length
map.
(fig 2) Determine
the hair density with a Density Map. Don’t forget to lessen the
amount of hair at the receding forehead corners and hair whorl (right
at the top of the head).
(fig 3) We
want the hair on the top to stick upwards, so use a negative Root Droop
and Tip Droop Map. A positive value also lets the side hair droop down.
(fig 4) Curl
the hair, mainly the upper head with a Curl Map.
(fig 5) Adjust
the amount of Clumps, the size and Skew with Clump Map
(fig 6 ) Distinguish
the direction of combing the hair: the upper and the sides with Surface
Comb Map.
(fig 7) Set
up the eyebrows with EyebrowMap.
(fig 8)
Set up the eyelashes with EyelashMap.
(fig 9) Set
up the beard with BeardMap.
(fig 10) For
the Surface(Smart) Combing, give different names to the tip of the nose
and the hair whorl. The whorl combing is especially useful to make the
hair flow away from this little bald spot.
Step 3 The Sasquatch settings
Let’s set up parameters with the weightmaps you
prepared. You will end up moving back and forth between weightmaps editing,
Sasquatch, and rendering until you figure out the best numbers. I am
warning you that this is the most time consuming part of the project.
So don’t give up!
We are now styling the hair so the rendering quality is not so important
here. So turn OFF Receive LightWave Shadows, Self Shadowing, and Enable
Cast Shadows. And I recommend turning on One-Pass Antialiasing reduce
rendering time.
(fig
11) Before Sasquatch. It’s a chrome dome!
(fig 12) To
begin with, set up the Fur/Fibers panel. For testing, keep the Fiber
Division low to save rendering time. Apply Density and Length to the
weightmaps you prepared and set the length and density of the hair.
Next, thicken the hair with Coarseness. Smaller Density values speed
up rendering. You can compensate by increasing Coarseness to keep the
hair coverage high. I left the density high for most of the hair close-up
shots so you could see the net effect clearly. When the hair is distant
from the camera, I strongly recommend that you experiment with the balance
of parameters such as Density, Coarseness and Fiber Divisions to speed
up rendering. Distant hair can look fine with much more aggressive settings
of low density and high coarseness, and the render time savings are
worth the effort.
(fig 13) Go
to Density’s S panel, and pick the Density map from Vertex Weight
Map. Base (Black) Value is the green area in the weightmap. Applied
(White) Value is the orange area. The rest of the weightmaps are set
up in the same way so I leave them out.
(fig 14) This
is the picture after setting just in the Fur/Fiber panel using Sasquatch’s
default settings. In this starting stage, it is just a fuzz ball with
too much density and length. It also looks flat since all the shadow
options are turned off but in turn the rendering speed is amazingly
fast. At this stage, the speed is much more important than seeing the
shadows.
(fig 15) Set
up the Styling panel. Set RootDroop and TipDroop on only the sides to
let the side hair droop down to the ground. And again control Curling
with a weightmap and set Tangle higher to let the whole hair entwine
and become a little ragged.
(fig 16) This
shows the result after applying the Styling settings. I've applied stronger
curling to the top of his head. Now his hair has changed from straight
hair to a bird's nest like mess!
(fig 17) Set
up the Clumping panel. The upper head has a higher value for Clump Haircount.
It’s better to have the sides smaller and also make them merged
closer to the tips by mapping the Clump Size and Matting Skew parameters.
These decrease the volume of the hairstyle, but Fiber Wiggle is a very
useful control to compensate for this decrease.
(fig 18) I
am using a lot of Clumping on top of the head. The sides have a lower
value. Using Matting Skew makes the top of the Clump merge closer to
the root parts. By adding Clump, the hair looks more greasy, like it’s
wet with hair gel (or sweat!). This is the look I want!
(fig 19) Set
up the Combing panel. Type the comb surface name (the tip of the nose
and the hair whorl) and Surface Comb only the sides. Use Comb Bias to
hold up the hair at the top of the head with the ( -) direction and
make the sides down further with the (+) direction. When doing these
settings, the short hair on the sides may go to the underneath the polygons,
so set Max Sleekness to 0% only to the sides.
(fig 20) Use
Surface Comb Strength to determine the direction of the side hair based
on the tip of the nose and the hair whorl. On the upper part of the
hair, use Combing Bias to hold the hair toward the (-) direction, meaning
toward the sky. Meanwhile, the side hair should be brushed down toward
the (+) direction, meanings toward the ground. This completes the styling
and combing phase.
(fig 21) Let’s
move on the Color panel. First, adjust the Salt and Pepper. What you
should do here is to decide how you want the hair to look when it's
lit.
(fig 22) Set
up the Shadowing. Turn on Self Shadowing, Receive LightWave Shadows
and Enable Cast Shadows to see how your hair responds to lighting. At
this moment, the hair looks blond.
(fig 23) Set
up the Shading panel to determine the attributes of the hair and its
darkness/brightness. Decrease Diffuse to make the originally blond hair
darker. And set Specular Tinting to make the hair look more realistic
when it is lit. The color you set on the Color panel shows up with specular
highlights, not diffuse lighting! This is like real hair and it helps
to make a realistic appearance.
(fig 24) After
adjusting the quality of the hair and darkness/brightness on the Shading
panel, increase Glossiness to get the look of shiny hair gel. Pay attention
to the fact that the specular highlight becomes the color of the original
blond hair. Again, this is the way real hair acts and you can see it
if you look around. It’s nice to recreate such a realistic phenomena
in the 3d world.
(fig 25) Use
weightmaps of EyeBrow, Eyelash, BeardMap for eyebrow, eyelash and beard.
The Sasquatch settings are done now!
Step 4 Lighting
There is no exaggeration to say that if you pursue realism
in 3DCG then the key skill is lighting. Even if an object has no texture,
it could feel very real if you use very correct lighting. If you cut
corners on lighting, no matter how elaborate the texture is, it will
just look fake. So I’d like to explain the lighting strategy I
used at in Step 3.
When it comes to a human face, my basic rule for lighting is that the
key light should come from the sides to make sure that one side has
visible cast shadows to show depth. I adjust the angle and position
of the key light to capture the specular highlights and to bring out
the attractive details of the skin. This is my own style and each artist
has their own thoughts.
I have the fill light coming from the opposite direction to avoid jet
black shadows. You want to (barely) see surface details even in deep
shadows. Use the rim light from the back of the head to capture the
outlines of the object that is shadowed because of the key light. This
method is also used for taking photos in real life.
(fig
26) Set up the scene with the three basic lights; Key, Fill
and Rim. Make these lights Spotlights with Falloff enabled.
(fig 27) This
is rendered with LightWave’s default light setting. The hair doesn’t
show depth because it has no darkness/brightness contrast. It looks
very flat. The default lighting is distant light so you have to change
all the lights into the combination of spotlight and shadow map to get
Sasquatch self shadowing.
(fig 28) Shadow
positions are determined by the direction of the key light. The specular
highlight on the skin helps show surface contours and details.
(fig 29) By
adding a Fill light, the outlines of the object appears from the shadows.
If the fill is too bright, the object will look too flat so deal with
it very carefully. The point is to just give a hint of knowing what
is in the shadow. It is a common error to have over-bright fill intensities!
(fig 30) A
Rim light helps show the details and shape of the hair even in the shadowed
areas. Rim lighting is very important to enhance the quality of the
hair especially around the outline of the head. Notice how the hair
is bright along the top, dimmer on the sides, and brighter just above
the ears. This contrast shows the depth of the hair. The theme of this
tutorial is “hair” so I used a stronger Rim light to accentuate
it.
Step 5 Rendering
Here's some different rendered views of the final style
Akira
Orikasa was born in the suburbs of Tokyo, Japan in 1973. After graduating
from a Japanese university majoring in Economics, he came over to the
USA and graduated from California State University, Chico with an Art
major. He has been working at Computer
Café as a lead visual effects artist since November 1998. The major
projects he worked oh as a lead artist are Panic Room (starring Jody
Foster, and directed by David Fincher), where he made more than 50 shots
including the opening title, and Spykids 2. Sees his resume
This tutorial first appeared
in the Japanese CG magazine ”Computer
Graphics World " magazine in June 2002. The face of the model
was later modified using G2. The title of the issue is “Challenge
of making realistic hair with Sasquatch!” You can see the movie
of the boxer in his site.