Shape Attributes

Sets per-vertex and per-path attributes on shape data, either from a spatial field or a uniform value. Enables per-path coloring, opacity, and stroke width in DrawShape.

Category: Shape Ops Menu path: Shape Ops > Shape Attributes

Ports

Port	Type	Direction	Description
shape_in	shape	input	Source shape
field_in	scalarField	input	Spatial field to sample at each vertex (also accepts vectorField and colorField)
out	shape	output	Shape with attributes set

Parameters

Param	Type	Default	Description
target	enum	Color	Which attribute to write: Color, StrokeWidth, Opacity, Rotation, or Custom
source	enum	Field	Field (use field_in or uniform value), Value (always uniform), Tangent (Rotation only — use per-vertex tangent), Index (sample ramp by per-path index)
value	scalar	1.0	Uniform value (used when source is Field with no connection, or source is Value)
colorValue	color	white	Color value (used when target is Color and source is Field/Value)
customAttribute	string	custom	Attribute key name (used when target is Custom)
tangentOffset	scalar	0	Degrees added to the computed tangent (only when target=Rotation, source=Tangent)
indexCurve	CurveRamp	0→1 linear	Sampled by per-path normalized index for scalar targets (source=Index)
indexColorRamp	GradientRamp	black→white	Sampled by per-path normalized index for Color target (source=Index)
groupAttribute	string	(empty)	Optional path attribute name. When set, paths sharing the same value form a group and share the sampled value — essential for text workflows (use glyphIndex) so multi-contour glyphs stay consistent.
outputMin	scalar	0	Lerp the [0,1] ramp / field output into [outputMin, outputMax]. Hidden for Color target and for source=Tangent or source=Value. Default 0/1 is identity
outputMax	scalar	1	See outputMin

How It Works

ShapeAttributes evaluates per vertex. For each vertex in the input shape:

1. If a field is connected to field_in, it is sampled at the vertex's position (origin-centered comp-pixel coordinates).
2. If no field is connected, the value or colorValue param is used uniformly for all vertices.

Attributes are written at two levels:

• Per-vertex (shape.points.attributes) -- used by DrawShape's per-vertex color pipeline for smooth GPU-interpolated gradients across triangles.
• Per-path (path.attributes, using the first vertex's value) -- used by DrawShape's grouped rendering for per-path color, opacity, and stroke width.

Target	Attribute key	Effect in DrawShape
Color	color	Per-vertex: smooth GPU-interpolated gradients. Per-path: uniform path color.
StrokeWidth	strokeWidth	Multiplier on DrawShape's strokeWidth param per path
Opacity	opacity	Per-path alpha multiplier
Custom	user-defined	Available for custom pipelines (consumer nodes decide what to do)

Custom target output type: The Custom target follows the field type of the connected input:

• ColorField -> Vec4 per vertex (and per path, from first vertex)
• VectorField (alone) -> Vec2 per vertex (bipolar [-1,1])
• ScalarField or uniform value -> Scalar per vertex

This mirrors PointAttributes' Custom target, so the same convention applies across points and shape vertices.

DrawShape rendering priority: When per-vertex color attributes are present, DrawShape automatically uses its DrawShapeVertexColor pipeline for smooth gradient fills. When only per-path attributes exist, it uses grouped rendering (one draw call per unique color/opacity/strokeWidth group). When neither is set, it uses a single uniform-color draw call.

Usage Examples

Basic: Gradient-colored shape

Rectangle -> SubdivideShape (gridSize: 10) -> ShapeAttributes (target: Color, field: Gradient.colorField) -> DrawShape. The rectangle fills with a smooth color gradient interpolated across its subdivided mesh.

Per-path stroke width

Grid -> CloneToPoints (shape: Circle) -> ShapeAttributes (target: StrokeWidth, field: Noise.scalarField) -> DrawShape. Each cloned circle gets a different stroke width based on its position in the noise field.

Opacity fade

EditableShape -> ShapeAttributes (target: Opacity, field: DistanceField.scalarField) -> DrawShape. Parts of the shape closer to another shape fade out.

Per-letter text coloring (Index source + glyphIndex grouping)

Text("HELLO") -> TextToShape -> ShapeAttributes (target: Color, source: Index, groupAttribute: "glyphIndex", indexColorRamp: red->blue) -> DrawShape. Each letter gets a distinct color sampled along the ramp; multi-contour glyphs like "O" keep their outer and inner paths the same color thanks to glyphIndex grouping.

Per-path progressive stroke width

A shape with N paths -> ShapeAttributes (target: StrokeWidth, source: Index, indexCurve: 0 -> 2). The first path has strokeWidth multiplier 0, the last has 2, linearly.

Tips

• For smooth color gradients, the shape needs interior vertices -- use SubdivideShape upstream to create a mesh with enough resolution for the gradient
• StrokeWidth is a multiplier on DrawShape's strokeWidth param, not an absolute value -- a value of 2.0 doubles the base stroke width
• ShapeAttributes does not change vertex positions -- it only writes attribute data. Use ShapeDeform for position changes.
• You can chain multiple ShapeAttributes nodes for different targets (e.g., one for Color, another for StrokeWidth)

Related Nodes

• PointAttributes -- same concept for points instead of shape vertices
• SubdivideShape -- create interior mesh vertices for smooth per-vertex gradients
• DrawShape -- reads color, strokeWidth, and opacity attributes
• CloneToPoints -- creates multi-path shapes ideal for per-path attributes
• Gradient -- colorField source for spatial color mapping
• DistanceField -- scalarField source for proximity-based attributes