pVortex

pVortex accepts an existing particle stream and applies a rotational force. Blackmagic describes the result as spiraling motion: particles inside the vortex pull are rotated and drawn toward the source of the Vortex. A minimal diagnostic graph is pEmitter → pVortex → pRender.

An important correction to the older article is the meaning of Power. Blackmagic's Fusion/Resolve reference says Power determines the degree to which Vortex Force Strength falls off with distance. It is therefore not just a vague second 'character' or strength control.

Strength determines the Vortex Force applied to each eligible particle. The captured Resolve baseline is 1.0; compare the same playback range with the node enabled and bypassed before increasing it.

Power changes distance falloff. With Strength fixed, near and far particles can respond differently, so a useful test needs particles occupying more than one distance from the vortex field.

The Translation section contains X Offset, Y Offset and Z Offset. Official documentation describes them as the amount by which the vortex offsets affected particles. In the UI they are also tied to positioning the vortex widget, so treat them as spatial translation/offset controls of the vortex behavior rather than an ordinary Transform of a finished image.

Size sets the size of the Vortex Force. It is a control of the force itself and is separate from the size of any selected Region. Prove pVortex first with Region Mode set to Ignore region so those two spatial concepts do not get confused.

Angle X and Angle Y control the amount of rotational force applied by the Vortex along the corresponding axes. They are not a conventional 3D image rotation. Change one axis at a time and judge particle trajectories during playback.

Random Seed/Reseed keep random behavior reproducible. Hold the Seed fixed while comparing Strength, Power, Offset, Size or Angle so two variables do not change at once.

Time Lock belongs to common particle random/time behavior. It does not freeze the simulation and does not replace pRender temporal controls such as Restart, Pre-Generate or Sub-Frame Calculation Accuracy.

Conditions > Probability filters eligible particles, while Age Start/End use normalized 0–1 particle lifespan rather than timeline frame numbers.

Set Mode and Set 1–32 filter Sets assigned upstream. pVortex does not create Set membership; assign it earlier with pEmitter, pImageEmitter, pChangeStyle, pSpawn or another compatible particle tool.

Region is a separate spatial gate. It decides where pVortex may act without replacing Strength, Power, Offset, Size or Angle. Keep Region Mode at Ignore region while diagnosing the core force.

Region Mode supports ignore, intersecting, inside, not intersecting, not inside, entering and leaving conditions. These change eligibility relative to a Region, not the vortex algorithm itself.

All, Bezier, Cube, Line, Rectangle and Sphere are built-in Regions and need no external cable. Bitmap and Mesh are different: selecting either creates a dynamic Region input.

Bitmap Region accepts a 2D image/selectable channel as a spatial gate. It is not an Effect Mask on finished RGBA and it is not the main Particles input.

Mesh Region accepts 3D mesh geometry and may expose surface/volume interpretation, winding and ObjectID controls. It gates spatial eligibility but does not turn pVortex into a renderer.

pVortex combines well with pDirectionalForce, pTurbulence and pFriction, but add them one at a time. Prove vortex motion first, then add broad drift, irregularity or damping so trajectory changes remain attributable.

Downstream pFriction can damp excessive accumulated velocity. Do not use friction as a substitute for correct Strength/Power setup: create the intended motion first and damp it separately.

The pVortex output is still particle data. Normal image tools such as Blur, Glow, Color Corrector and Merge belong after pRender, where the particle stream becomes a visible 2D image or 3D particle output.