Houdini 20.5 Nodes Geometry nodes

Hair Clump 2.0 geometry node

Clumps guide curves together.

Since 17.0

The center and shape of each clump can be controlled using explicitly provided curves or a set of curves selected from the input curves.

Parameters

General

General

Blend

Blends the overall effect of the operation.

Clump Size

Create clumps of this size. When no clump curves are provided, uses a a set of curves from the first input with that are spaced such that clumps have roughly this size.

When clump curves are provided via the first input, use the clump size as the influence radius.

This parameter can be overridden using an attribute or texture. To do this, select an option from the drop-down menu next to the parameter.

Search Beyond Clump Radius

Curves are affected even if they are outside of the radius of all clump curves.

Crossover Rate

This parameter can be overridden using an attribute or texture. To do this, select an option from the drop-down menu next to the parameter.

Random Seed

The seed used for various random effects.

Shape

Preserve Length Differences

Ensure that relative length differences among the curves of a clump are preserved. When disabled, the points of each curve are simply moved towards the corresponding location on the clump curve, which causes the tips of all curves to end at the same location. This is faster but tends to look less natural.

Extend To Match

Extends all curves such that the longest curve in a clump reaches the tip of the clump curve’s tip.

Shorten To Match

Shortens all curve such that the longest curve in a clump is just long enough to reach the clump curve’s tip.

Accurate Bundling

Take into account the width of curves for clumping (as defined by the width attribute). This prevents curves from collapsing onto the clump curve where tightness is 1.0.

Hair Width

Use this width for Accurate Bundling when curves have no width attribute.

Hair Width Scale

Multiply curve width by this value for the purpose of Accurate Bundling.

Tightness

Controls how tightly curves are clumped.

This parameter can be overridden using an attribute or texture. To do this, select an option from the drop-down menu next to the parameter.

Stray Amount

Amount to stray from the clump. Higher values cause clump curves to have less of an effect. This effect is usually limited to a percentage of curves using the Stray Rate parameter.

This parameter can be overridden using an attribute or texture. To do this, select an option from the drop-down menu next to the parameter.

Stray Rate

The percentage of curves to which are allowed to stray from their clump.

This parameter can be overridden using an attribute or texture. To do this, select an option from the drop-down menu next to the parameter.

Stray Falloff

Controls the strength of the stray effect with distance from the clump center. Higher values cause curves close to the center to stray less.

Clump Profile

Controls the tightness of the clump along it’s length.

Fractal Clumping

Fractal clumping performs multiple iterations of clumping with smaller clump sizes.

When providing clump curves, they are used for the first iteration. Successive iterations use a subset of curves from the input guide curves. The density and size of these clumps is defined by the Clump Size.

Iterations

Clump this number of times.

This parameter can be overridden using an attribute or texture. To do this, select an option from the drop-down menu next to the parameter.

Goal Feedback

Controls how much the clumping effect of an iteration feeds into the clump curves of the next iteration.

A value of 0.0 causes each iteration to be performed as if nothing had happened before it.

A value of 1.0 uses the curve shapes computed in the previous iteration.

This parameter can be overridden using an attribute or texture. To do this, select an option from the drop-down menu next to the parameter.

Size Reduction

Reduce clump size by this factor after each iteration.

This parameter can be overridden using an attribute or texture. To do this, select an option from the drop-down menu next to the parameter.

Tightness Reduction

Reduce tightness by this factor after each iteration.

This parameter can be overridden using an attribute or texture. To do this, select an option from the drop-down menu next to the parameter.

Curling

Curling

Curls clump curves before performing clumping.

Amplitude

The radius of the curl effect.

This parameter can be overridden using an attribute or texture. To do this, select an option from the drop-down menu next to the parameter.

Amplitude Ramp

Controls the amplitude along the length of the curve.

Frequency

The number of full turns per length unit.

This parameter can be overridden using an attribute or texture. To do this, select an option from the drop-down menu next to the parameter.

Frequency Ramp

Controls the frequency along the length of the curve.

See also

Geometry nodes