Creating and Animating Fur in Maya

590GM, Fall 2004

This is a tutorial describing how to create hairy or furry objects in Maya(tm), and how to animate the fur in response to external forces such as wind.

Table of Contents

  1. Maya Basics
    1. Moving the camera
    2. Creating and manipulating objects
    3. Rendering the scene
  2. Creating Fur
    1. Using a preset hair style
    2. Changing the hair parameters
  3. Animating Fur
    1. Attractors and fields
    2. Rendering the animation
  4. Conclusion

I. Maya Basics

Maya is installed on all the machines in GRAIL (Allen Center 291), and in the video editing room (Allen Center, 290). If you can't access these rooms, please send mail to snavely@cs.washington.edu, and we'll try to work something out.

To run Maya, select Start > All Programs > Alias Wavefront > Maya 5.0 > Maya Unlimited 5.0. Let's first learn how to create objects and move the camera. When Maya starts, it brings up a window asking you to view a few tutorials. These are each about a minute long, and it's worth it to watch the first three of them, which show how to move the camera; move, rotate and scale objects; and create objects.

A. Moving the camera

Maya opens up a perspective view of an empty scene by default. To manipulate your view of the scene, use the <Alt> key in combination with one of the three mouse buttons: <Alt>+<Left button> rotates the scene, <Alt>+<Middle button> translates the camera in the plane (pans), and <Alt>+<Right button> zooms in and out.

B. Creating and manipulating objects

In Maya, you can create either NURBS objects or polygonal objects. Let's first create a NURBS sphere. To do this, click on the Create menu and select NURBS Primitives > Sphere (the little boxes on the right side of the menu options bring up advanced options, which we won't need in this tutorial). This creates a sphere at the origin, which is shown as a wireframe object.

To manipulate the sphere, use the toolbar along the right-hand side of the screen. Here's what the toolbar looks like, as well as a description of each tool.

The Select Tool: Select objects in the scene.

The Move Tool: When the Move tool is active, a widget with three arrows will appear, centered on the selected object, one for each of the X, Y, and Z axes. Clicking on one of the arrows will allow you to move the object along that axis. In addition, by clicking on the little yellow window that appears where the three axes meat, the object can be moved in a plane passing through the object, perpendicular to the view direction.

The Rotate Tool: When the Rotate tool is active, three circumferences of a sphere appear around the selected object, one around each of the X, Y, and Z axes. Clicking on one of the circumferences allows you to rotate the object about the respective axis. A fourth circle, colored yellow, allows you to rotate the object about an axis parallel to the view direction.

The Scale Tool: Finally, the Scale tool brings up a widget similar to the move widget. In this case, dragging one of the three arrows scales the object non-uniformly along that axis; clicking and dragging the center of the widget scales the object uniformly.

C. Rendering the scene

To create a rendering of the scene, just hit the Render the current frame button in the toolbar at the top of the screen. After a few seconds, a rendering will appear. By default, this is a 320x240 image, rendered from the current viewpoint. Although you may not have created any lights, you will probably still be able to see the objects in the scene; apparently a default light is used if none are specified.

To change the rendering options, open the Render Globals window by clicking on the Display Render Globals window button . Later on, we will show you how to render multiple frames of an animation.

II. Creating Fur

A. Using a preset hair style

 While Maya objects are bald by default, giving them a nice coat of lush fur is extremely simple. Just follow these steps:

  1. Create an object to apply fur to (either use the one you created in part I.B. or create a new scene and select Create > NURBS Primitives > Sphere).
  2. Select the sphere using the Select tool .
  3. Select the Fur tab in the tabbed toolbar near the top of the screen:



    This toolbar has a set of pre-defined hair and fur styles, from bear to wet otter. Select the Lion Mane style.
After a moment, you will see wavy lines grow out of the sphere. This is a visualization of how the hair will look when the scene is rendered. Render the scene (see Section I.C. above) to get an idea of how the furry sphere looks.

The hair may not be lit well at first, so you may want to add some lights to fix this. To do so, select Create > Lights > Directional Light (or create a different kind of light, such as a spot light). Lights can be manipulated with the same set of tools as objects.

B. Changing the fur parameters

The Lion Mane fur is just a set of preset parameters controlling the style and look of the hair, as are all of the pre-defined fur styles. You can experiment with these parameters by doing the following:

1. Select the fur by clicking on one of the strands (note that this is different from selecting the sphere itself).
2. Open the Attribute Editor pane, by clicking on the Show or hide Attribute Editor button , found in the toolbar in the top right corner of the screen.

This pane should open up on the left side of the screen, and looks like this:


In this window, you can change the color and opacity of the fur (both the root and the tip can be edited). To edit the color, just click on the colored boxes to bring up a color chooser. There are also a host of more interesting parameters that control a variety of fur characteristics, such as "Length," "Scraggle," and "Clumping." It's fun to play with each of these to see what they do. The fur visualization responds immediately when a parameter is changed, giving you a rough idea of the effect of the change.

III. Animating Fur

A. Attractors and Fields

Maya gives you several ways to create animations. To animate the fur, we'll investigate Maya's tools for applying dynamics to a scene (though it is also possible to animate hair using keyframe animation). In Maya, dynamics can be applied to different kinds of objects, such as rigid bodies and particle systems. Fur is considered a kind of particle system. However, the individual strands are not the particles in the system. Instead, we create a sparse set of attractors on the furry surface; each attractor influences nearby strands of fur on the surface. The attractors act like particle-spring systems, and move in response to forces in the system; the hair, in turn, responds to the motion of the attractors.

To animate the fur, follow these steps:

  1. Select the sphere object using the Select tool (you should click on the wireframe of the sphere, and not the fur itself).
  2. Make sure that the Rendering menu set is selected, by choosing Rendering from the menu set combo box at the top right of the screen (it is set to Animation by default; each setting displays a different set of menus).

    The Fur menu should appear to the left of the Help menu.
  3. Select Fur > Create Attractor...
  4. In the Create Attractor dialog box, change "Attractor Length" to 1.0, and hit the "Create" button. Several strange purple objects should now be protruding from the sphere. These are the attractors.
  5. Notice the Selection Mask toolbar near the top of the screen:

    This can be used to mask out certain kinds of objects from selections. In this case, we only want to apply dynamics to the attractors, and not the sphere itself (for now, we want the sphere to stand still). Unselect all of the masks except the Dynamics mask , so that this toolbar looks like this:


  6. Zoom out so the attractors are visible in their entirity. Using the Select tool, click and drag a box that surrounds all the attractors. If the Attribute Editor pane is open, you should see tabs for "spring9" and "springShape9."
  7. Click on the Dynamics tab to bring up the Dynamics toolbar:



    This toolbar lets you create particle systems, forces, and special effects such as fire.
  8. Let's create some wind to blow the hair a bit. Click on the Air Field button to create a new directional force for the scene. This will appear as a small "fan" icon in the middle of the view. You can move it away from the sphere using the normal object move tool to make the icon easier to see. By default, the air field "blows" in the positive Y direction, but this can be changed by editing the attributes of the air field in the Attribute Editor pane.
  9. Since the attractors were selected when we created the air field, the field will apply a force to the attractors (if a field is created without another object being selected, the field needs to be explicitly set to affect an object). To see the effect of the field on the attractors, press the play button in the toolbar on the lower right of the screen. This will run the animation for a small number of frames; you should see the attractors moving as the animation progresses.

B. Rendering the animation

Although we can see the attractors moving when we play the animation, it's hard to see how the hair moves. In order to get a better idea of what's going on, we should render an animation. Here are the steps for doing this:
  1. Click the Display Render Globals button . This opens the Render Globals dialog. Under "Image File Output," create a new filename prefix and select "name.#.ext" from the "Frame/Animation Ext" combo box. Change "Image Format" to the kind of file you want to produce (such as AVI or TGA). Next, change "End frame" to however many frames you want to render (twenty seems like a good lower bound). bound). Hit the Close button.
  2. Click on the Rendering tab to bring up the Rendering toolbar:




  3. Click on the Batch Render button (there are two buttons with this icon, you watch the one on the left). This will start the rendering in the background. The files will be written to the directory "C:\Documents and Settings\\My Documents\maya\projects\default\images". The progress of the rendering will be displayed in the lower right corner of the screen; it will probably take a few minutes to render.
  4. Once the rendering is done, look at the results! (Note: I think there's a way to view the results from within Maya, using the Show Batch Render button in the Rendering toolbar, but I haven't been able to get this to work. I've just looked at the output files to see the results.)

IV. Conclusion

Congratulations! You have successfully completed this tutorial. You are now ready to move on to the tasks.
Please send questions to Noah Snavely (snavely@cs.washington.edu)