Everything in the above scene is done with this method.
Let us start by making a simple shape........
If you want to use my rock, here you go!
I want to make a painted rock, like in the above scene. Why?... Because I like rocks... they are our friends... they speak to me.........
1. Make a rock out of polys, mine is roughly 3.2 units wide. Why 3.2?...I don't know.
I haven't tried Nurbs, but I'm sure it works.
Now that rock rocks!
2. Apply Automatic mapping to the rock.Fur needs good mapping coordinates to sit right on the surface.
Note: Use the default settings, or whatever it happens to be set to.
In this case, since we are creating an Impressionistic style, so Uv's don't have to be perfect. It only needs to cover the whole mesh somewhat evenly. If you want to take a look at your Uv's, open the Uv Texture Editor.
Window>Uv Texture Editor.
This is what my rock's Uv's look like. You can use this window to "Cut and Sew" your Mapping Coordinates if you like, but that my friends, is a rock of a different color. If you use bitmaps to drive your color...I would suggest the Cut and Sew method to get perfect Uv's. For now leave it alone... it won't matter for this tutorial.
UV Editing is soooo much fun!
Next we create the shader for the rock....
If you want to skip the shader part... here is the rock scene without fur attached... the cheater...:-)
We are going to drive all Appearance Attributes in the shader without use of 3d lights. I am doing it this way because I want to simulate a painting style. You don't paint with lights in your paint, so I am going to have all shapes fully Incandesent.
Start by opening the Hypershader window. Window>Rendering Editors>HyperShade...
1. Create a Lambert. Since we are using only incandescence and no lights, it doesn't really matter what shader type you use. Lambert is fast (yeah right!) for rendering time.
2. Select your Lambert Node and hit Show Up and DownStream Connections.
Click on the Work Area button.
The work area appears. WOW!!!
2. Add a Snow Texture to the Incandescence. Keep the 3d Placement Node. We will use this to control light direction. Use the settings in the image below.
Note: Click Show Up and DownStream Connections again. Do this often. It keeps your work area nice and tidy.
3. Now for some variety in the shader, add a Brownian. You could do without this, but it adds small variations in the final fur render, much like paint.
4. Double click on the Brownian, name it "Top" and set the weight3d to x1 y10 z1. See below for settings. I use this setting for a flat rock because it "flattens" the noise and creates a layered sedimentary look.
5. Now Connect the Top Brownian to the SnowColor in the snow node by Middle Mouse dragging the Brownian Node to the Snow Node and selecting "Other".
This opens the Connection Editor.
6. Left click on Out Color in Outputs. Then Left Click on Snow Color in Inputs. Close the Connection Editor. You could use other methods for connecting things in Maya. However, I prefer the Connection Editor because you can connect many different Attributes in ways you wouldn't normally think of -- like using the OutColor of Ramp to drive the Translation of a Sphere.
7. Do the same as step #3-6 for the Snow SurfaceColor, but name it "Bottom".
8. Now create a Ramp texture. Delete 2d placement if you want, you don't need it for what we are doing here.
9. Adjust the colors of the ramp so that it is a light color at the bottom and black at the top.
10. Connect the ramp to the Color Offset of the first Brownian (Use the steps from Above for the Connection Editor).
11. Do the same as step #8-9 for the second Brownian. Except make the ramp darker colors than the first ramp.
12. Now we use the mighty SamplerInfo Node. Create one and connect "Facing Ratio" of the Sampler Info node to each of the ramps "vCoord"Attributes.
Note: This can be found under "UvCoord" using the Connection Editor.
The reason for using a SamplerInfo Node with a Ramp, is to force the color to change from the bottom of the Ramp to the top of the Ramp based on the angle of the surface to the camera. In other words, as the surface turns toward the camera, the renderer calculates its color from the bottom to the top of the Ramp.
The SamplerInfo Node can be used for many camera based effects... including shaders that change according to distance from the camera or its position in 3d space. Experiment with this Node. It is very powerful.
12. Now use the IPR to have some fun playing with the snow settings (and any other nodes' setting for that matter). Also, change the rotation of the 3d Placement Node on the Snow Texture if you want to move the simulated light direction.
Note: You can choose whatever colors you want... but the idea is to have the SnowColor to be very different than the SurfaceColor.
You should have something like this now:
13. Turn off primary visibility for the rock in render stats. This is so that no "hard" edges show through.
14. Make sure to delete whatever lights there are after you are finished. Just to keep the scene clean.
OK, now the Furry Fun begins!
1. Create a new fur description for the rock. Fur>Attach Fur Description>New
Edit the fur description in the Attribute Editor. If it doesn't open automatically, select the fur hairs and hit Ctrl-a.
2. In the Fur Feedback Shape, turn up the Fur Accuracy all the way to 1.
3. Use the Attribute Map Width and Height to turn up the detail of the Color Map that is used for the coloring. I have it set to 512 x 512.
4. Click on the FurDescription tab.
5. Note: You will want to Name your FurDescription when your scene gets more complex.
6. Connect the shader you made to the Base and Tip ambient color channels on your fur description. Do step #6 by Middle Mouse Dragging form the Hypershade Window to the Checker colored buttons next to Base and Tip Ambient channels in the Attribute Editor.
7. Set your fur description setting to match the screenshot below. I use the fur to create swirls of brush strokes. Makes sense, right? Paint brushes are made out of hair.
- If you want to use lights, Don't set the light model to Ambient only.
- Use Inclination, Roll, and Polar to control the direction and how much the fur "lays" on the surface.
- Adjust the Base and Tip Opacity to "blend" your brush strokes.
- Base and Tip Width will control the taper of your brush.
- Base and Tip curl will control movement of your stroke application... swirls, broad strokes, etc...
- Scraggle randomizes your strokes.
8. Now hit the Bake button. This creates the color maps for the fur.
9. Render the scene.
You should have something like this:
Turn up density to 3000 and....
That's really about it...
Play around with all the attributes... you can get some interesting results.
- Click here for some examples using different layer modes in post: Water Color Pastel
- You can also use Artisan to brush the direction and length of the strokes.
- Get creative with shader networks. Use a shader that changes with distance to simulate fog effects.
- REMEMBER to hit the Bake button if you change the camera angle or any of the shader attributes. This shader is dependent on camera direction.
- You don't have to not use lights.
- Use a Switch Utility Node to vary your shader to use on more than one object.
- The only downfall so far is that you have to bake for every frame when you animate. I'm sure there is a way to automate this... but I don't know it. If anyone does know... send me an e-mail... I would be most grateful. Or we could discuss it in the Maya forum at CreativeCOW.net.