Guide Utility geometry node

Snaps guide curves to a skin surface and creates a roots point group.

On this page	Inputs Parameters Snap to Skin Create Roots Group
Since	22.0

This node provides common utility operations for guide and hair curves:

Snap to Skin moves curve points so they sit on the skin surface. This is useful after operations that may have pulled curves off the skin, such as smoothing or manually editing guide positions.
Create Roots Group creates a point group containing only the root point (first vertex) of each curve. This is a convenience for downstream nodes that need to operate on roots.

Inputs ¶

Guide / Hair Geometry

The guide or hair curves to process.

Skin Geometry

The skin mesh used for snapping. Required when Snap to Skin is enabled. The node uses existing skinprim and skinprimuv attributes on the curves to locate each curve’s root on the skin surface. If these attributes are missing, the Guide Skin Attribute Lookup SOP inside the HDA computes them from the current curve and skin positions.

Parameters ¶

Group

Subset of input primitives to process. Leave empty to process all curves.

Snap to Skin ¶

Snap to Skin

Enable snapping curve points to the skin surface. When enabled, each curve’s root position is projected onto the skin using skinprim/skinprimuv attributes, and the resulting offset is applied according to the Mode.

Treat Skin as Subdivision Surface

Evaluate the snap position on the OSD limit surface rather than the polygon surface. Enable this when the skin mesh is a subdivision surface to get a smoother, more accurate snap target. This uses osd_limitsurface() internally.

Mode

Controls how the snap offset is applied to each curve.

Whole Curve

Translates every point on the curve by the same offset, so the entire curve moves rigidly to match the skin position. This preserves the curve’s shape.

Root with Falloff

Applies the full offset at the root and linearly decreases it to zero at the tip. This snaps the root to the skin while leaving the tip in place, producing a smooth blend.

Root Only

Moves only the root point. All other points remain unchanged. Use this when you only need the root to touch the skin and want to avoid disturbing the rest of the curve.

Create Roots Group ¶

Create Roots Group

Create a point group containing the root point (first vertex) of each curve.

Roots Group

Name of the point group to create. Defaults to roots.

Merge Op

How to combine with an existing group of the same name.

Replace

Overwrite the existing group.

Union with Existing

Add to the existing group.

Intersect with Existing

Keep only points that are in both the new and existing groups.

Inputs ¶

Parameters ¶

Snap to Skin ¶

Create Roots Group ¶

Geometry nodes