Primitives & Tracks

An effect can change eight things. Each one has its own value type and its own rule for combining contributions from effects that run at the same time.

You're at the deepest level. Every primitive and every driver is open here, and nothing is hidden underneath: the Effect builder and the ready-made tracks are made from these same pieces. You can still drop ready-made tracks into any effect where they fit.

Tracks

A track is a flat table tagged by Primitive. Every track accepts these two fields:

Every primitive except Sound also needs a Driver that produces its value type:

Which drivers fit

Drivers don't belong to a primitive. A driver fits a primitive when it produces that primitive's value type: FOV, Blur and Overlay (its opacity) take a number, Position and Rotation a Vector3, Color a ColorValue, and Vignette a number or a VignetteLayer. With --!strict, a track whose driver doesn't fit is underlined in your editor.

✓ fits directly. via … means wrap it first, for example Drive.Modulate(Drive.Constant(Vector3.new(0, 0, 4)), envelope) to give a Vector3 the envelope's shape. Sound takes no driver.

FOV

A delta in degrees, added to the camera's base FieldOfView. Positive values widen the view (a punch outward) and negative values narrow it (zoom in). Contributions add up. If other code changes the FOV, CameraRig adopts the new value as the base instead of fighting it.

{ Primitive = "FOV", Driver = Drive.Spring({ Kick = 7, Frequency = 3.5, Damping = 0.4 }) }

Drivers that fit

Position

A camera-space offset in studs: X is right, Y is up and Z is back. Contributions add up.

-- Kick the camera back 0.18 studs
{ Primitive = "Position", Driver = Drive.Spring({ Kick = Vector3.new(0, 0, 0.18), Frequency = 9, Damping = 0.45 }) }

Drivers that fit

Rotation

An Euler offset in degrees as (pitch, yaw, roll). Contributions add up. This is the main ingredient of most shakes.

{ Primitive = "Rotation", Driver = Drive.Modulate(Drive.Noise({ Frequency = 14, Amplitude = Vector3.new(3, 3, 6) }), envelope) }

Drivers that fit

Blur

A BlurEffect.Size. The strongest contribution wins instead of summing, so two blurs don't stack into a white-out. MotionFX creates its own MotionFX_Blur in Lighting when it is first needed and destroys it when idle.

Drivers that fit

Color

A ColorValue table, applied through MotionFX's own MotionFX_Color ColorCorrectionEffect, so it never fights your Lighting setup.

-- Flash: brighter and desaturated, fading over 0.7 s
{ Primitive = "Color", Driver = Drive.Modulate(Drive.Constant({ Brightness = 0.25, Saturation = -0.35 }), Drive.Envelope({ Release = 0.7 })) }

Drivers that fit

Vignette

A plain number from 0 to 1 is a black vignette at the screen edge. A VignetteLayer gives you control over colour, placement and images:

• Contributions with the same Inset and Image share a layer, and the strongest one wins, including its colour and size.
• Different layers stack, with the outermost drawn on top. An Image layer is drawn above a gradient layer with the same Inset.
• A gradient layer with Inset > 0 is a soft ring. It is clear at the edge, peaks at its Inset, and fades toward the centre.
• Gradient layers are built from four edge frames with UIGradients, so they need no image asset. The ScreenGui is created on first use and destroyed when idle.

-- Outer dark edge, plus a deep red ring inside it
{ Primitive = "Vignette", Driver = Drive.Modulate(Drive.Constant(0.85), flash) },
{
	Primitive = "Vignette",
	Driver = Drive.Map(flash, function(amount: number): Types.VignetteLayer
		return { Intensity = amount * 0.7, Color = Color3.fromRGB(120, 0, 0), Inset = 0.3, Size = 0.9 }
	end),
},

Drivers that fit

Sound

Sound is event-based rather than continuous, so it has no driver. Each Sound track spawns its own Sound in SoundService once its Delay has passed. Its volume follows Volume × intensity × Weight × fade.

Overlay

A flipbook of images drawn over the screen, from sprite sheets or a folder of numbered images. Its driver is the opacity, 0 to 1, so any number driver works: an envelope to fade in and out, noise to flicker, a binding to follow game state. Like Sound, overlays aren't combined; each track shows its own image, above the vignette. See Overlays for sheets, Track.Overlay and the Overlay maker.

{ Primitive = "Overlay", Sheet = splatterSheet, Fps = 30, Driver = Drive.Envelope({ Attack = 0.05, Release = 0.6 }) }