Animate spline primitives using an Anim Wires modifier

You can use an Anim Wires modifier to animate the splines in your hair fur groom or instanced splines. After adding the modifier, you can attach a hair system to the anim wires so that Maya drives the animation wires using the dynamic output curves from an nHair system.

You can use an Anim Wires modifier with splines Description regardless of how they are generated( set by Generate the Primitives) or controlled (set byControl the Primitives by). See Create hair or fur using spline primitives.

Tip: Before adding an Anim Wires modifier:

• Shape the splines in to a base style or pose. See Shape and Control XGen Primitives.
• In the XGen Editor toolbar, clearing the preview () and turning off Update Preview Automatically can make the point map generation faster and the maps's control markers easier to see.

Add the Anim Wires modifier and setup the points map

1. In the XGen Editor, click the Modifiers tab.
2. Click this icon to open the Add Modifier Window.
3. Click to add an Anim Wires modifier, and then click OK.

   An Anim Wires modifier is added to your Description's modifier stack.

   Now specify a control map for the modifier.

4. Under Anim Wires Modifier, in the Control Map section, set Use Dir to one of the following:
   • Default, if your Description does not have a Clumping modifier.
   • Clumping, if your Description has a single Clumping modifier.

     The Anim Wires modifier uses the points map from the Clumping modifier.

   • Default, if your Description has more than one Clumping modifier.
5. Click Create Maps.
6. In the Points section of the Generate Maps window, set the Density and method for generating the point map. XGen creates an animation wire for each point in the map.
   Tip: The easiest way to create a points map is to set the points Density to a value between 1 and 3, and then click Generate. If your Description has guides, you can also click Guide to create a point at each guide location.

   Yellow point markers indicate the locations for the animation wires.

   For more information about point maps, see Create point maps for XGen modifiers.

7. If your Description does not have a Clumping modifier, click Create.

   Maya generates the points map for the animation wires. You can now generate output curves and attach the nHair system (see below).

   If your Descriptions have one or more Clumping modifiers, you must specify a control map for the Anim Wires Modifier modifier.

8. To specify a control map, in the Maps section, do one of the following:
   • If your Description has a one Clumping modifier, turn on Use Control Maps.
   • If your Description has multiple Clumping modifiers, turn on Use Control Maps, and beside Control Map, ensure the path is set to Clumping1, so that the Anim Wires uses the control map from the first clumping modifier in the stack.

     For example replace Clumping2 with Clumping1.

9. Click Create.
10. (Optional) In the XGen Editor, under Control Map click Preview Wires to display the animation wires.
11. (Optional) To improve playback performance and render time of the animated splines, add a Groom Bake modifier to the top of the modifier stack.
    

    For more information, see Groom Bake modifier.

Generate the output curves and attach nHair

1. In the Control Map section, select Create Hair System.
2. In the Make Curves Dynamic Options window that appears, do the following:
   • Set Output to NURBS Curves.
   • Ensure all other options are turned on.
   • Click Make Curves Dynamic.

   The dynamic curves now drive the animation wires.

3. In the Outliner, expand hairSystemOutputCurve group and select the output curves.

   Note that you must select the curves individually, not the hairSystemOutputCurve group.

4. In the Control Map section of the XGen Editor, click Attach Hair System.

   The animation wires now inherit the curve's dynamic animation, which is generated by the Nucleus solver.

5. (Optional) Click Preview Regions to see which areas are affected by the modifier.
6. Rewind to the start frame and play back the animation.
   Note: If the curves do not animate, rewind to the start frame, and play back the simulation again.
7. (Optional) To increase playback time, cache the nHair, by selecting hairSystem in the Outliner, and then in then FX menu set, select nCache > Create New Cache > Create New Cache > nObject > > .

You can now animate the Anim Wires by applying other Modifiers to the splines , such as a Wind or Directional Force modifier.

With the groomed objects in a base-pose (initial frame), the wires should be static so that a reference wire pose can be stored. Wire animation can start after this initial frame state. At render time, each spline is bound to the static reference wire and then animated. See XGen patches.

For information about setting the initial state for the nHair system, see Set hair curve positions and Start Rest and Current Position curves.

Related tasks

• Save and setup dynamic curves for rendering
• Animate hair, fur, or instanced splines using nHair
• Animate guides by attaching an nHair system