Work with Clump modifiers

Consider these workflow tips when working with Clump modifiers:

• Use a Density Mask to control the distribution of hair clumps on the surface of the mesh. You can then connect the same masking texture file to the Clump attribute to more accurately control magnitude of the hair clumps. See Work with masks.
• Move the Clump modifier up or down in the modifier stack to get the best desired effect. For example, the hair clumping may look different depending on whether it comes before or after a Noise or Sculpting modifier.
• To sculpt individual hair clumps, select them using the Freeze tool, then turn on Invert Frozen.
• If you are not satisfied with the placement and appearance of the hair clumps, regenerate the clump points using a different seed value. To do this, in the Clump Point attribute group, set Seed to a new value.
• To create secondary hair clumps, make sure that the Map Subdivision Level Attribute value for the primary and secondary clumps are the same. An easy way to do this, is to duplicate the primary clump by right-clicking and selecting Duplicate from the menu that appears.

  Adjust the Density value in the Clump Points attribute group on the secondary Clump modifier so that it is higher than the Density value of the primary Clump modifier. This ensures that the clumps from each secondary Clump modifier reside within the map subdivisions of their respective primary Clump modifiers. Otherwise, the secondary clumps can be influenced by points in other neighboring primary modifiers, creating undesired results.

• If you see jagged artifacts in the hair clumps, increase the Map Subdivision Level attribute in the Clump Map attribute group. This increases the resolution of the clump map.

Create curls and coils in the hair

To create curls and coils in the hair, try starting with the following settings:

• Increase the number of CV's on the hairs to a value between 24 and 36. To do this:
  1. In the Interactive Groom Editor, select the description_base node.
  2. In its CV Settings attribute group, enter a value for CV Count, and then click Rebuild.
• Use Curl values greater than 1, and then use the Curl Scale ramp to define the shape.
• If needed, you can increase Offset to allow room between each clump for the curls or coils.
• You can create a random expression to vary the direction of the curls. To do this:
  1. Click the texture map icon beside Curl.
  2. In the Create Render Node window, and under Maya, select Utilities.
  3. Select Xgm Se Expr from the list.

     An xgmSeExpr expression node is created and connected to the Clump modifier node.

  4. In the xgmSeExp attributes, type a randomize expression beside Expression.

     For example, rand(1,-1). You can also click Open SeExpr Editor and type the expression into the editor.

Related topics

• XGen interactive grooming Clump modifier attributes