Point Delete

Removes points or shape vertices where a mask value exceeds a threshold. Polymorphic — accepts either a Points or a Shape stream, outputs the same type.

Category: Point Ops Menu path: Point Ops > Point Delete

Ports

Port	Type	Direction	Description
in	points	input	Points or shape to filter (shape vertices are treated as points)
mask_in	scalarField	input	Optional scalar field sampled at each element's position to drive deletion
out	points	output	Filtered stream (type mirrors input)

Parameters

Param	Type	Default	Description
rule	enum	By Attribute	What marks an element for deletion: By Attribute (a selection over any attribute, intrinsic, or the mask field), Range (an element-order span), Every Nth (periodic thinning — no attribute needed)
attribute	string	(empty)	By Attribute rule: the column read when mask_in is disconnected — an attribute, group, or intrinsic. Empty deletes nothing
attrRule	enum	Member	How the value marks an element: Member (> 0.5 — "delete the group", no extra knob), Greater Than, Less Than. Committing an intrinsic auto-flips Member to Greater Than
attrValue	scalar	0	Comparison operand for Greater Than / Less Than. Hidden under Member
rangeFirst / rangeLast	scalar	0 / 9	Range rule: inclusive @index span to delete
everyN / everyOffset	scalar	2 / 0	Every Nth rule: delete element i when (i − offset) mod n = 0
invert	boolean	false	Flip any rule into "keep only these" — keep the group / span / every Nth, delete the rest

How It Works

PointDelete resolves a per-element scalar mask, then keeps elements whose mask value is at or below threshold (or above, when invert is set).

Mask resolution priority:

1. If mask_in is connected, sample the scalar field at each element's position.
2. Otherwise, read the named scalar attribute from the element stream. Missing attribute → mask = 0 → element kept.

Shape handling: when a vertex is deleted, adjacent segments are rewired as straight-line bridges across the gap. Original bezier segments whose endpoints are both kept preserve their control points. Paths with fewer than 2 remaining vertices are dropped. PointIds are preserved, so downstream cache keys remain stable for elements that survive.

Per-vertex / per-point attributes (color, scale, opacity, custom, etc.) are filtered in parallel with the element list, so a downstream DrawShape or DrawPoints continues to render per-element variation correctly.

Intrinsic Names

Any attribute-name field here also accepts an intrinsic — a property every element has by virtue of existing, computed on read and never stored. The leading @ is a reserved namespace: no attribute may be named with one, so a name starting with @ never hits the attribute map.

Name	Value
@index	Position in the list, starting at 0
@id	Stable PointId — survives filtering and reordering
@x / @y	Position, in local geometry space
@n	Total number of elements
@indexnorm	@index / (@n - 1), normalized 0–1
@rand01	Deterministic 0–1 per element, keyed on @id (stable as neighbours come and go)

Names are case-insensitive (@Y = @y). A misspelled intrinsic (@bogus) resolves to nothing rather than falling through to an attribute lookup.

Non-scalar attributes reduce to a scalar by one rule everywhere: Vec2/Vec3 → magnitude, Vec4 → Rec.709 luma of RGB.

So attribute = "@y", threshold = 300 deletes every element above y = 300 — a filter that previously had no node in the catalog, because position was a struct field rather than an addressable name.

Usage Examples

Delete points inside a shape

Grid → PointDelete (mask_in: DistanceField from some shape, threshold: 0.5) → DrawPoints. Points inside the shape's distance field get removed, leaving only those outside.

Attribute-driven subset

Grid → PointAttributes (target: Custom, customAttribute: "selection", field: Noise.scalarField) → PointDelete (attribute: "selection", threshold: 0.7) → DrawPoints. Points where the noise field exceeds 0.7 are deleted.

Sparse cloned shapes

Grid → PointDelete (mask_in: Random.scalarField, threshold: 0.8) → CloneToPoints (shape: Circle) → DrawShape. Randomly thin out the grid to about 20% of points before cloning.

Tips

• Binary masks (scalar values of exactly 0 or 1) work as hard on/off switches with the default threshold of 0.5
• Smooth fields give soft cutoffs — raise or lower threshold to control how aggressive the deletion is
• Use invert when you want to keep the selected region and delete everything else
• For shapes, deletion can split a closed path into disconnected pieces if enough interior vertices are removed — use ResampleShape upstream to densify first if you need smoother results after deletion
• No per-path deletion yet; this node works at the vertex/point level. A future ShapeDelete node may add path-level filtering

Related Nodes

• PointAttributes — write the selection attribute (or any named scalar) that PointDelete consumes
• ShapeAttributes — write per-vertex attributes on shapes
• AttributeToField — bridge per-element attributes into field space for FieldMath composition
• FieldMath — combine multiple fields before feeding mask_in (e.g. multiply by a distance field to restrict the deletion region)
• DistanceField — common mask_in source for "delete inside/outside this shape" workflows