Create interactive groom hairs, guides, and wires from existing curves

You can use curves from the current Maya scene or an Alembic cache file to generate hairs, guides, and wires. The curves can originate from content creation applications other than Maya, and they can be static or animated.

Before continuing make sure you have done following:

• Created an interactive groom description. See Create hair and fur using interactive grooming tools.

  You can use the default settings for creating the hair. The curves you add override many of these settings.

• Added a Curve to Spline or Guide modifier to the description. See Working with interactive grooming modifiers.

Create hair from existing curves using a Curve to Spline modifier

Create hair from curves in the scene

1. Select the curves in the scene.
2. Crtl + click the curveToSpline modifier in the XGen Interactive Groom Editor.
3. In the modifier's Attribute Editor, for Input From, enable Curves and disable Cache.
4. Click Add Selected Curves.

Maya creates interactive groom hairs from the selected curves. In the Attribute Editor, Input lists the names of the input slots on the Curve to Spline node, while Curve Name lists the curve attached to the input.

You can remove a curve by selecting it under Input or Curve Name and then clicking Add Selected Curve.

Create hair from curves in an Alembic cache file

1. In the XGen Interactive Groom Editor, select the curveToSpline modifier.
2. In the modifier's Attribute Editor, under for Input From, disable Curves and enable Cache.
3. In the Input Cache section, click the browse icon and locate the Alembic cache file containing the curves.

   Maya creates interactive grooming splines from the curves in the Alembic cache file.

Create guides from existing curves

You can use a Linear Wire modifier in this workflow instead of a Guide modifier, although some settings may be different.

Create guides from curves in the scene

1. Select the curves in the scene.
2. Crtl + click the Guide modifier in the XGen Interactive Groom Editor.
3. In the Input Guide section of Attribute Editor, click Use Selected Curves as Guide.
4. In the Use Selected Curves as Guide Options window, select one of the following:
   • Delete Curves to permanently remove the source curves from the scene.
   • Preserve Dynamic Link to maintain the links between the source curves and the target guides. This way, curve edits and animation get automatically applied to the guides. This option is useful when using one set of curves as the source for guides in multiple descriptions.

     Turn on Preserve Dynamic Link when driving guide shape and animation using nHair dynamic output curves.

   Maya creates a transform_fromCurve sub-description node, and a xgmCurveToSpline node, which generates the guides from the shape and animation of the curves.

Create guides from curves in an Alembic cache file

1. In the Interactive Groom Editor, select the Guide modifier.
2. In the Attribute Editor, locate the Input Guide attribute group, and click Create.
3. In the Interactive Groom Editor, expand the Guide modifier and select the InGuide node.
4. Select Add Modifier, and then select Curve to Spline.
5. Follow the steps from Create hair from curves in an Alembic file above to generate guides from curves in an Alembic cache file.

Continue modifying the groom

You can continue modifying the groom by doing the following:

• Sculpting the hairs using the interactive grooming tools. To do this, place a Sculpt modifier above the Curve to Spline or Guide modifier in the stack, select it, and begin sculpting using an interactive grooming tool.

  See Work with sculpt layers.

• Add more modifiers to shape and control the hair. See XGen Interactive Grooming Modifiers.
• Use the hairs from the description to shape hairs in other descriptions. See Control multiple descriptions using a Guide or Linear Wire modifier.
• Simulate the hairs by adding a Linear Wire or Guide modifier. See Simulate hair using a Linear Wire modifier.