Attach Hair Curves to Surface

The Attach Hair Curves to Surface node binds hair curves to a surface mesh, establishing their attachment positions and optionally aligning them to the surface orientation. This node is a fundamental part of hair generation and grooming workflows, ensuring that curves remain anchored correctly to the underlying surface, even after deformation or topology changes.

Note

This node or modifier requires valid Surface geometry or object inputs, as well as a Surface UV Map, to function properly.

Inputs

Geometry

The input geometry containing the hair curves to be attached to the surface.

Surface Input Type

Defines how the surface geometry is provided for attachment. The geometry input takes priority if both are connected.

Object:

Use an object reference as the target surface.

Geometry:

Use a geometry input directly connected to the surface mesh.

Surface

The surface object or geometry used as the attachment target. Its transforms must match the modifier object for proper alignment.

Surface UV Map

The UV map used to determine the attachment points on the surface mesh. These coordinates are stored per curve to maintain attachment consistency.

Surface Rest Position

When enabled, sets the surface mesh into its rest position before attachment. This ensures consistency when later deforming curves along the same surface.

Tip

When using this node with Deform Curves on Surface, enable Surface Rest Position if that operation comes after this one, so the attachment coordinates are recorded in the pre-deformed state.

Sample Attachment UV

Samples the Surface UV Map at the attachment point and stores the UV coordinates for each curve. This allows later nodes to access or reuse the attachment data.

Snap to Surface

Projects the root of each curve onto the closest point of the surface mesh, ensuring that all roots lie directly on the surface.

Align to Surface Normal

Rotates each curve so that its root direction aligns with the surface normal. This typically requires guide data or consistent curve orientation to produce stable results.

Blend along Curve

Blends the deformation or alignment effect gradually along each curve, from root to tip, instead of applying it uniformly.

Outputs

Geometry

The resulting geometry with updated curve attachments.

Surface UV Coordinate

The UV coordinate on the surface mesh corresponding to each curve’s attachment point.

Surface Normal

The normal vector of the surface mesh evaluated at each curve’s attachment point.