For Each Element Zones

A For Each Geometry Element zone runs a block of nodes once for each element of a geometry, such as each point or each face.

Use the @for_each_element decorator, and choose the domain with domain=:

@for_each_element(domain="POINT")
def ball_per_point(index: int, radius: float):
    ball = uv_sphere(radius=radius).mesh
    return ForEachResult(
        main={"scale": radius * 2.0},
        generated=[{"geometry": ball, "id": index}],
    )

@tree("Balls")
def balls(geometry: Geometry):
    points = mesh_to_points(mesh=geometry).points
    radius = random_value(min=0.05, max=0.2).value
    result = ball_per_point(points, radius=radius)
    return result.generated.geometry

When calling the zone, pass the geometry first. Every other parameter is an input of the zone, evaluated as a field on the geometry, so each element receives its own value. You can also pass selection= to only run the zone for some elements.

Two parameter names are special and are not inputs:

• index receives the index of the current element.
• element receives the current element as its own geometry.

Results

The zone function returns a ForEachResult:

• main values are stored as attributes on the input geometry, one value per element.
• generated is a list of groups. Each group starts with a geometry, followed by attributes stored on it. The geometry from every element is joined.

The zone’s outputs are split the same way. result.main.geometry is the input geometry with the main attributes, readable as result.main.scale. result.generated.geometry is the joined generated geometry.

If you only need main values, return a dictionary instead of a ForEachResult.