Displaces every point of a host by a per-point amount that follows a field's weight — translating, scaling, and rotating a cloner's clones, or displacing a mesh or spline's vertices — the general-purpose way to sculpt field-by-field.
Declarative element:
<sk-simple-point-constraint>
Not on the sk.* global — construct via the declarative element or a module import.
This is the general-purpose member of the PointConstraint family: like
every point-constraint it runs a GPU kernel over all of its host's points at once —
the clones of a sk-cloner, or the vertices of a mesh or spline — so it stays
cheap at huge point counts. It samples a SpatialField at each point to get a
weight in [0, 1], then applies animatable transform deltas scaled by that weight —
with no field, the deltas apply at full strength everywhere.
Key attributes. field names the SpatialField to sample by #id. Each
clone is then displaced by animatable deltas scaled by its field weight: translate
dx/dy/dz (added × weight) and scale dsx/dsy/dsz (columns scaled by
1 + delta × weight) are the workhorses. Also available are rotation dh/dp/db
(Euler heading / pitch / bank × weight), position-scale sx/sy/sz (push each
point toward or away from the world origin, or a pivotNode when one is set), and
field-weight-range, which remaps
the raw weight before it scales the deltas. All deltas default to no-effect, so set
only the ones you want — no mapping expressions needed, and every delta is animatable.
On a cloner every delta applies; on a mesh or spline host, whose output carries only
vertex positions, the position deltas (dx/dy/dz, sx/sy/sz) take effect
while the per-clone rotate/scale deltas have no per-vertex slot.
Related. Sibling point-constraints specialise the kernel:
sk-radial-push-point-constraint pushes clones from an origin,
sk-target-at-point-constraint aims each clone at a node, and
sk-custom-wgsl-point-constraint runs an arbitrary WGSL kernel. Its
single-node CPU cousin is sk-field-constraint.
constructor(config?: { field?: Field; dx?: number; dy?: number; dz?: number; dsx?: number; dsy?: number; dsz?: number; dh?: number; dp?: number; db?: number; sx?: number; sy?: number; sz?: number; dQuaternion?: Quaternion; pivotNode?: SceneNode | null; fieldWeightRange?: readonly [number, number] })Inherited from: PointConstraint, SkenraAnimatable
— see those pages for inherited members.
| Property | Type | Default | Description | Declared by |
|---|---|---|---|---|
fieldanimatableread-only |
Field |
— | The field used by this point constraint, if any. | PointConstraint |
dxanimatable |
number |
0 |
Position delta X. | SimplePointConstraint |
dyanimatable |
number |
0 |
Position delta Y. | SimplePointConstraint |
dzanimatable |
number |
0 |
Position delta Z. | SimplePointConstraint |
dsxanimatable |
number |
0 |
Scale delta X (additive: final scale factor = 1 + dsx × weight). | SimplePointConstraint |
dsyanimatable |
number |
0 |
Scale delta Y (additive: final scale factor = 1 + dsy × weight). | SimplePointConstraint |
dszanimatable |
number |
0 |
Scale delta Z (additive: final scale factor = 1 + dsz × weight). | SimplePointConstraint |
dhanimatable |
number |
0 |
Rotation heading delta (radians). | SimplePointConstraint |
dpanimatable |
number |
0 |
Rotation pitch delta (radians). | SimplePointConstraint |
dbanimatable |
number |
0 |
Rotation bank delta (radians). | SimplePointConstraint |
sxanimatable |
number |
1 |
Multiplicative position scale X (scale = 1 + (sx - 1) × weight). | SimplePointConstraint |
syanimatable |
number |
1 |
Multiplicative position scale Y (scale = 1 + (sy - 1) × weight). | SimplePointConstraint |
szanimatable |
number |
1 |
Multiplicative position scale Z (scale = 1 + (sz - 1) × weight). | SimplePointConstraint |
dQuaternionanimatable |
Quaternion |
— | Rotation delta as quaternion. Slerped by field weight in the compute shader. | SimplePointConstraint |
pivotNode |
SceneNode | null |
— | Optional SceneNode whose world position defines the pivot point for position scaling. | SimplePointConstraint |
fieldWeightRangeanimatable |
readonly [number, number] |
— | The [lo, hi] range the normalized field weight maps onto. |
PointConstraint |
| Property | Type | Default | Description | Declared by |
|---|---|---|---|---|
targetread-only |
ConstrainablePointsHost | null |
— | The target host this modifier applies to, or null before |
PointConstraint |
sceneread-only |
any |
— | Gets the Scene this animatable belongs to, if any. | SkenraAnimatable |
animationsread-only |
SkenraAnimation[] |
— | Public getter for the animations affecting this target. | SkenraAnimatable |
| Method | Description | Declared by |
|---|---|---|
animate(firstArg: TypedKeyframe<this>[] | TypedPropertyIndexedKeyframes<this> | Record<string, any> | globalThis.Keyframe[] | globalThis.PropertyIndexedKeyframes | null, secondArg?: number | KeyframeAnimationOptions | globalThis.KeyframeAnimationOptions): SkenraAnimation & Animation |
Creates a new SkenraAnimation for this target per Web Animations API. | SkenraAnimatable |
removeAnimation(animation: SkenraAnimation): boolean |
Removes a specific animation from this object. | SkenraAnimatable |
constrain(type: K, config: ConstraintConfigMap[K]): ConstraintReturnMap[K] |
Creates a constraint on this Animatable using a fluent API. | SkenraAnimatable |
const modifier = new SimplePointConstraint({
field: sphericalField,
dy: 5, // translate up to 5 units up where field weight = 1
dsx: 2, // grow X up to 3× (1 + 2) where field weight = 1
});
cloner.addPointConstraint(modifier);