Houdini 16.5 Hair and Fur

Creating and styling fur with guide processes

To create fur, start with a piece of geometry and use the Add Fur tool on the Hair Utils shelf. By default, two nodes are created: Guide Groom and Hair Generate.

The red curves in the viewport represent guide hairs that you can style. You can use the tools on the Guide Process tab to style the fur. Typically the first thing you’ll want to do is set the direction of the fur by using the Initialize Guides tool. You can then use the Wind Direction parameter to set the direction of the fur and the Lift slider to create an initial look.

Next you can use the Set Length tool to lengthen or shorten the hairs. Turning on the Randomize checkbox will give the fur more varied length, creating a more natural look.

You can also create bends in the straight fur by using the Bend tool on the Guide Groom shelf. This allows you to determine where the hair will curve using the Curve Mask Ramp (for example just at the tip of the strand) as well as the Angle at which it will bend.

Once you're finished styling the fur you can turn off the display flag on the Guide Groom object. The Hair Generate object takes the guide curves and generates hair from them.

Tip

You will need to render the Hair Generate node, not the Guide Groom node. However, the Hair Generate node pulls its data from the Guide Groom node, so you will need to turn the display back on before rendering.

There is checkbox called Limit to bounding box on the Hair Generate object that allows you to focus on a patch of fur instead of having to wait for the entire surface area of the fur to cook as changes are made.

You can the change things like the Thickness and Density until you get the look you want.

Tip

If you can’t see the generated hair properly, turn on High Quality Lighting form the Display options toolbar on the right side of the viewport. Also click and make sure Ambient Occlusion is enabled.

You can also dive inside the Hair Generate object and click the Clump tool on the Guide Process tab to add clumping to the fur. You can adjust the Clump Size and Iterations on the Fractal Clumping tab to make the look of the clumping more natural for your model. Turning on Curling will also give your fur a more natural look. By default the Amplitude is set to 0 so you don’t see any changes initially.

Masterclass

Hair and Fur

Working with fur

Tools for creating fur

  • Add Fur

    Adds fur to a surface.

  • Create Guides

    Creates a guide curves from a skin geometry or manipulates the guides of another groom object.

  • Draw Hair

    Lets you add freehand-drawn hair guides to a fur object.

Tools for styling with guide processes

  • Initialize Guides

    Gives the guides an initial direction.

  • Curve Advect

    Advects curves using a vector field generated from curves drawn on the skin surface.

  • Reguide

    Interpolates guides between planted guides.

  • Set Direction

    Points guides in the direction of a vector.

  • Set Length

    Lengthens or shortens guide hairs.

  • Lift

    Lifts curves off the skin or flattens them against it.

  • Straighten

    Straightens the hair by bending each segment back so that it’s in the same direction as the previous segment.

  • Smooth

    Blends the shapes of the neighboring guides to create a smoother look.

  • Frizz

    Offsets the curve points along the guide hairs to create a frizzy look.

  • Bend

    Bends curves in a certain direction and by a certain angle.

  • Clump

    Creates bunches of guide hairs.

  • Part

    Lets you draw a parting line on the skin geometry.

  • Add White Hairs

    Adds the required attribute to mark hairs as white hairs in the standard hair shader.

Tools for styling with brushes

  • Screen Brush

    Lets you interactively groom hair in screen space.

  • Surface Brush

    Lets you interactively groom hair along the surface of your geometry.

  • Lift Hair

    Lets you interactively push hair away from the surface.

  • Clump Hair

    Lets you interactively pull hair into a clump.

  • Part Hair

    Lets you interactively push hair away from your stroke.

  • Length Adjust

    Lets you interactively vary the length of the ends of the hair.

  • Smooth Hair

    Lets you interactively smooth areas of hair.

  • Cut Hair

    Lets you interactively trim hair.

  • Extend Hair

    Lets you interactively lengthen hair.

  • Recache Strokes

    Recaches recorded strokes in all Guide Groom SOPs within a groom object.

Tools for animating and simulating fur

How to