How does the new geometry node Deform Curve on Surface work?

Question

Does anybody have information about the new Deform Curve on Surface node? How does it work?

Answer 1

The Deform Curves on Surface node is used to attach the new hair curves of Blender 3.3 to a surface, e.g. the head or body. It is needed when the surface is deformed by a modifier such as the Armature, Wave, or the Subdivision Surface modifier.

To work properly, the surface object must be UV unwrapped and there must be no overlapping UV islands. Also, it needs the curve attribute surface_uv_coordinate. If there is something wrong you get a warning/error message in the status bar and it won't work properly.

When you add a Curve > Empty Hair object to a selected object, Blender creates a Curve object, automatically makes it a child of the selected object, and adds a Geometry Nodes modifier with only a single Deform Curves on Surface node to the new curve object.

Example of the default cube with a level 3 Subdivision Surface modifier and hair curves:

Disabled the Geometry Nodes modifier with the Deform Cuves on Surface node and the hair follows the original mesh of the default cube:

For more info, see:

• Blender.Today LIVE #199

• D14864 Curves: Deform curves based on surface node.