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Shag:Hair - How to paint Fur / Hair (Part 1)
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I've found one of the most commonly overlooked features of Shag:Hair is its ability to key off sub-id materials
and bitmaps, allowing you to affect the properties for a referencing hair or fur object.That's why I call it "painting
hair" - paint a bitmap and you can paint exactly where you want your hair or fur to be. And that's not all...
The tutorial here shows you how to use this cool technique.
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1) Download and unzip the file shag1start.zip. This has a max file with an object
/ lights / camera setup, and a grayscale bitmap that you'll use for hair placement.
3) Open up Material Editor and make a new Multi/Sub-Object
material, calling it "Fur". Set its number of Sub-Materials to 2.
a) Call Material #1 “Skin Color.” Set both the ambient and diffuse colors to white.
b) Call Material #2 “Fur Grayscale.” Add the grayscale bitmap included
in the zip file to the diffuse map channel.
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(btw - all the materials already exist in material editor if you're feeling lazy today :)
4) Assign this new “Fur” Multi/Sub-Object material to the plane object in the viewport.
5) Go to Rendering>Environment>Atmosphere and add a Shag:Render
and a Shag:Fur effect to the atmosphere list. Highlight the Shag:Fur effect to edit it.
6) In the Shag:Fur objects panel, select the plane object in the viewport as your emitter. You should see a ShagView object appear on it's surface (called SF_plane01_01)
7). Open the Material Editor and create a new Standard material called “Fur Color.” Make its diffuse and ambient colors something bright (e.g. RGB:135, 25, 255), so you can clearly see what
the fur is doing.
8) Assign this "Fur Color" material to the ShagView object that was created in the scene (SF_Plane01_01).
9) Go back to edit your Shag:Fur effect in the atmosphere list. In
the parameters panel, set the "Density Per Area" value to something pretty dense like 10 (this high value is
just to make sure you can clearly see what the fur is doing). |
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10) Set the Length Maximum to 5, then check the SubMat ID box and set the ID to 2. This tells the fur emitter that it's going to key off material #2 in the Multi/Sub-Object
material you created.
11) Render away! (and if it all goes a bit pear-shaped here's the file all finished
for you)
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Wow, so what's happening here? Well, since you set the sub-material ID to 2, the fur length is now keyed off the
grayscale bitmap in that sub-material. The color Black (RGB:0,0,0) translates to length 0, the color White (RGB:255,255,255),
translates to the max length 5, and the gray values are all lengths in between depending on brightness.
Using this technique its also possible to affect the many other
Shag properties such as density, thickness, curliness, etc. - all in exactly the same way. You can even key off additional
sub-materials in the multi/sub-object material if you want, as in this file.
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This technique also works for the Shag:Hair effect too - except that
you do need to define a "model hair" for your ShagView object. You'd do that right after point 6, where as well
as substituting "Shag:Hair" for "Shag:Fur" in the above instructions, you would..
6a) ...unhide the hair-like spline in the file you downloaded. Unhide
it by going to the Display panel, select"unhide by category" and "unhide shapes."
6b) Select the spline "ModelHair" and apply a Shag:Hair
"Model Hair" modifier to it.
6c) Open the Shag:Hair effect Objects/Model Hairs selection panel
and select the hair. You should see hairs sprout all over the surface of the plane.
6d) Then carry on with instructions at point 7... (note that model
hairs have a max length of 1.0 which is the percentage length of the model hair that's being referenced).
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And that's how you affect hair / fur with sub-id materials and painted bitmaps!
Using a combination of these techniques, that's how I put fur
on my penguin model. The penguin had very thin, very short hair/feathers round the head, ranging down to longer
thicker hair/feathers round his feet – all keyed off different sub-materials with grayscale bitmaps controlling
the length, thickness, density and color.
Since this technique lets you use a simple bitmap to define hair length and where hair is (or isn't), IMHO it makes
tools like the modelling cutters a little redundant. These days, I find it way easier to just hop into Photoshop
and paint bitmaps - placing or "cutting" hairs that way.
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