pPointForce

pPointForce applies a force emanating from one point in 3D space. It is not a screen-space Transform or a regular mask: the node changes particle velocity relative to a point-force center and passes particle data downstream.

The sign of Strength is fundamental. In Blackmagic's current particle reference, positive values are attractive and pull particles toward the point, while negative values are repulsive and accelerate particles away from it. Comparing equal positive and negative magnitudes is the fastest sanity check for the field direction.

Power controls how force strength falls off with distance. Power 0 produces no distance falloff; higher values make the force decay increasingly sharply away from the center. Power is not a Radius or Region size control.

Limit Force is often misdescribed as a generic maximum-force limiter. The reference gives it a more specific purpose: reducing overshoot around the point-force center caused by temporal sampling. A particle can step past the center between samples and then be thrown away in the opposite direction; increasing Limit Force reduces that risk.

Limit Force therefore belongs to temporal stability as well as artistic tuning. Blackmagic notes that particle position is normally sampled once per frame unless sub-frame calculation is increased in pRender. For center overshoot, inspect both Limit Force and pRender temporal/sub-frame accuracy rather than only lowering Strength.

In the captured Resolve Inspector the point position appears under Translation as X Offset, Y Offset and Z Offset. The manual describes the same concept as X/Y/Z Center Position: these coordinates move the force point in 3D, not the rendered image and not the Region geometry.

Random Seed and Reseed provide reproducible random evaluation where the particle tool uses randomness. Keep the seed fixed while diagnosing Strength or Power so a new random sample does not hide the causal change.

Time Lock belongs to the node's common random/time behavior and is not a particle-simulation freeze. It does not replace correct pRender Pre-Roll or sub-frame evaluation.

Conditions Probability is evaluated for each eligible particle on each frame. A value such as 0.6 does not choose one permanent 60-percent subset for the entire lifespan; every particle receives the same chance again on the next frame.

Age Start/End is a normalized 0–1 portion of particle lifespan, not timeline frame numbers. This can leave the launch phase untouched and enable point attraction only later in life.

Set Mode and Set 1–32 filter particle Sets that were assigned upstream. pPointForce does not create Sets in the Conditions tab; generators and Set-changing particle nodes assign those groups earlier in the stream.

Region is not the attraction target. X/Y/Z Offset defines the point-force center, while Region only determines where the node is allowed to act. The force point and a Sphere Region can deliberately be placed at different coordinates.

By default pPointForce has only the Particles input. All, Bezier, Cube, Line, Rectangle and Sphere are built-in Regions and need no second cable. Bitmap and Mesh are the exceptions: choosing either adds a dynamic Region input.

Bitmap Region uses a 2D image/selectable channel as a spatial gate. It is not an Effect Mask and not the particle stream. Mesh Region uses 3D mesh geometry and supports surface/volume interpretation, winding controls and ObjectID filtering.

Line Region spans two XYZ points; Rectangle is planar with no intrinsic Z depth even though it can be positioned and rotated in 3D; Cube and Sphere provide built-in volumetric gates. None of these Region geometries changes the Strength/Power falloff itself.

Region Mode chooses the relationship to the selected Region: ignore, intersecting, inside, not intersecting, not inside, entering or leaving. Prove basic attraction/repulsion with Ignore region before adding spatial gating.

A clean baseline graph is pEmitter → pPointForce → pRender. pDirectionalForce or pTurbulence can add drift and organic variation, while downstream pFriction can damp accumulated velocity, but pPointForce is easiest to diagnose before those layers are added.

The pPointForce output remains Particles. pRender is required to produce a visible 2D image, or can convert the stream into a 3D particle output for a 3D pipeline. pPointForce itself never produces RGBA.

Judge the node over time. Attraction, overshoot, falloff and Probability are temporal behaviors, so a single still can hide a problem or make Power and Limit Force appear ineffective.