Circle

The Circle Image Generator draws a perfectly smooth disk, ring or ellipse, procedurally and at any resolution. Because it is computed rather than drawn with points, its edges stay crisp at any size, and every setting can be animated, linked or driven by other Generators.

Use it for:

• Dots, badges, rings and other simple graphic elements
• Animated pulses, ripples and loading indicators
• Soft spotlights, glows and vignettes
• Round masks and mattes

Quick Navigation

• Creating and Connecting a Circle
• Disk or Ring: the Edge Mode
• Keeping Proportions with the Radius Scaled Modes
• Soft Edges with Feather
• Inverting the Circle: Holes and Vignettes
• Drawing an Ellipse
• Motion Blur
• Controls

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Creating and Connecting a Circle

Like any Image Generator, the Circle can be connected to any image parameter, for example:

• The Source of a layer, to display the circle itself
• The Mask of a layer, to reveal that layer through a round or soft-edged shape
• The image input of a Modifier, for example to use the circle as a matte or a map that drives an effect

The quickest way to create a layer with a Circle as its source is described in Adding Layers:

• Click the + button at the top of the layer stack and choose Circle from the list of Generators
• Place the mouse cursor over the Viewer and open the Quick Access Menu, then pick Circle:
  • Press Q when no layer is selected
  • Press Shift+Q when a layer is selected (in this case, Q opens the menu dedicated to Modifiers)

To use it with any other image parameter, such as a Mask, click the parameter's slot and choose Circle from the list of Generators on the right.

By default, you get a white disk with a Radius of 100 pixels, centered in the composition. The center of the circle is set by the Offset parameter, in pixels, relative to the center of the composition: positive X values move it to the right, positive Y values move it up.

Disk or Ring: the Edge Mode

The Edge Mode menu decides whether the Circle is a filled disk or a ring, and how the ring is measured.

• None: draws a filled disk of the given Radius
• Edge Radius: draws a ring between two radii. Radius is the outer edge and Edge Radius is the inner edge, so a Radius of 170 with an Edge Radius of 110 gives a ring 60 pixels wide. Use it when you need exact inner and outer sizes, for example to fit a ring around another element.
• Thickness: draws a stroke of the given Thickness, centered on the Radius. Half of the stroke is drawn outside the Radius and half inside, so a Radius of 170 with a Thickness of 40 covers the area between 150 and 190 pixels.
• Radius Scaled Thickness: draws a stroke like Thickness, but the Thickness is a percentage of the Radius, so the ring keeps its proportions when the Radius changes. See Keeping Proportions with the Radius Scaled Modes.
• Radius Scaled Thickness & Feather: same as Radius Scaled Thickness, and the Feather sizes are scaled too.

Keeping Proportions with the Radius Scaled Modes

In Thickness mode, the stroke keeps the same width in pixels whatever the Radius. This is what you want for a clean outline, but when the circle grows or shrinks during an animation, a fixed stroke can look too heavy on a small circle and too thin on a large one.

The Radius Scaled Thickness mode solves this by expressing the Thickness as a percentage of the Radius: with a Thickness of 20, the stroke is always 20% of the Radius, and the ring keeps its proportions at any size.

The Radius Scaled Thickness & Feather mode goes one step further and also scales the Feather sizes with the Radius, so a soft ring keeps exactly the same look while its size is animated.

Soft Edges with Feather

Two parameters soften the edges of the circle:

• Feather Outer Size softens the outer edge
• Feather Inner Size softens the inner edge of a ring

The feather is centered on the edge: it fades out on both sides of it, so the circle keeps the same apparent size while you soften it. Large Feather Outer Size values on a filled disk turn the Circle into a soft spot of light, ideal for glows and spotlights.

Inverting the Circle: Holes and Vignettes

Enabling Invert swaps the inside and the outside of the circle: the color fills everything around the circle, and the circle itself becomes a transparent hole. This is useful to cut a round hole in a solid color, or to create a vignette, as described below.

The result depends on the Output Format, which defines the size of the image produced by the Generator:

• With Auto (the default), the image is only as large as the circle itself, including its feather. When inverted, only this square is filled, and the color stops at its border.
• With Unbounded, the image has no limits, and the inverted area fills the whole frame.

Creating a Vignette

A vignette darkens the edges of the frame to draw the eye to the center. The Circle creates one in a few clicks:

1. Add a Circle layer on top of your composition.
2. Enable Invert, and set the Color to black.
3. Set the Output Format to Composition Format. The circle becomes an ellipse that touches the four edges of the frame (see Drawing an Ellipse), so the vignette always follows the shape of your composition.
4. Increase Feather Outer Size until the darkening fades smoothly toward the center.

Use the alpha of the Color to control the strength of the vignette: lower values let more of the image show through in the corners. For a rectangular vignette with rounded corners, use the Constant Generator instead.

Drawing an Ellipse

When Output Format is set to Format Preset, Composition Format or Custom Format, the Circle behaves differently: it ignores Radius and Offset, and draws the largest ellipse that fits inside that format. This gives you an ellipse whose width and height you control independently.

• Composition Format: an ellipse that touches the four edges of the composition
• Format Preset: an ellipse that fits the selected preset, such as Square 512
• Custom Format: an ellipse that fits the rectangle you define with the Format parameter (left, bottom, right, top, in pixels from the center of the composition)

Motion Blur

When the circle moves quickly, because its Offset or Radius is animated, the Circle can render its own motion blur. Increase Divisions to enable it: this is the number of samples taken during the shutter interval, and higher values give a smoother blur at the cost of render time. Shutter Angle sets the length of the blur, and Shutter Phase sets when the shutter opens relative to the current frame. See Motion Blur for more details.

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Controls

Parameter / Script Name	Type	Default	Function
Enabled / enabled	Boolean	On	Turns the Generator on or off. When off, the Generator produces an empty image.
Output Format / output_format_mode	Choice	Auto	Defines the size of the generated image. See Inverting the Circle and Drawing an Ellipse. - Unbounded: The image has no limits. Use it with Invert. - Format Preset: Draws an ellipse fitting the selected preset. - Composition Format: Draws an ellipse fitting the composition. - Custom Format: Draws an ellipse fitting the Format rectangle. - Auto: The image fits the circle, including its feather.
Format / format_preset	Choice	HD (1920x1080)	The format used when Output Format is set to Format Preset. - PC VIDEO (640x480) - NTSC (720x486:0.91) - PAL (720x576:1.09) - NTSC 16:9 (720x486:1.21) - PAL 16:9 (720x576:1.46) - QHD (960x540) - LHD (1280x720) - HD (1920x1080) - VHD (1080x1920) - UHD 4K (3840x2160) - VUHD 4K (2160x3840) - UHD 8K (7680x4320) - Super35 1K FULL AP (1024x778) - Cinemascope 1K (914x778:2.00) - Super35 2K FULL AP (2048x1556) - Cinemascope 2K (1828x1556:2.00) - DCP 2K (2048x1080) - Super35 4K FULL AP (4096x3112) - DCP 4K (4096x2160) - Square 256 (256x256) - Square 512 (512x512) - Square 1K (1024x1024) - Square 2K (2048x2048)
Format / formatRect	Float 4D	-500, -500, 500, 500	The rectangle used when Output Format is set to Custom Format, as left, bottom, right and top edges in pixels from the center of the composition.
Pixel aspect / par	Float	1	The pixel aspect ratio of the generated image.
Offset / offset	Float 2D	0, 0	Position of the center of the circle, in pixels from the center of the composition. Positive Y values move the circle up.
Radius / radius	Float	100	Radius of the circle, in pixels. In Edge Radius mode, this is the outer edge of the ring.
Color / color	Color	1, 1, 1, 1	Color and opacity of the circle.
Colorspace / input_colorspace	Choice	Project Display Space	Only available when the composition's Color Management is set to OpenColorIO. The colorspace in which the colors of this Generator are expressed. - Project Working Space: The color is assumed to be expressed in the project working space - Project Display Space: The color is assumed to be expressed in the project display space
Edge Mode / circle_edge_mode	Choice	None	Chooses between a filled disk and a ring. See Disk or Ring. - None: Draw a filled disk. - Edge Radius: Draw a circle by specifying the inner and outer edge radii. - Thickness: Draw a circle by specifying its radius and the stroke thickness. - Radius Scaled Thickness: Draw a circle by specifying its radius and the stroke thickness, and scale the thickness by the radius. - Radius Scaled Thickness & Feather: Draw a circle by specifying its radius and the stroke thickness, and scale the thickness and feather size by the radius.
Thickness / thickness	Float	10	Stroke thickness, centered on the Radius. In pixels in Thickness mode, and as a percentage of the Radius in the Radius Scaled modes.
Edge Radius / edge_radius	Float	10	Inner edge radius, in pixels. Only used in Edge Radius mode.
Feather Outer Size / feather_outer_size	Float	0	Softness of the outer edge. The feather is centered on the edge.
Feather Inner Size / feather_inner_size	Float	0	Softness of the inner edge of a ring. Has no effect when Edge Mode is None.
Invert / invert	Boolean	Off	Fills the area outside the circle instead of the inside. Use with Output Format set to Unbounded to fill the whole frame.
Divisions / divisions	Float	1	The number of samples to use for the motion-blur. The higher the number is, the more accurate is the motion-blur when large motion is involved, but the slower it is to render.
Shutter Angle / shutterAngle	Float	180	The shutter angle controls the time period over which light can pass. A wider angle increases motion-blur
Shutter Phase / shutterPhaseType	Choice	Centered	- Centered: The shutter opens half the shutter duration before the current time and closes half the shutter duration after - Start: The shutter opens at the current time and closes after the shutter duration is elapsed - End: The shutter opens at the current time minus the shutter duration and closes at the current time - Custom: The shutter opens at the time determined by a custom phase: the phase is an offset on the shutter angle, assuming the shutter opens at 0
Custom Phase / customPhase	Float	-90	An offset to the shutter angle, assuming the shutter opens at 0: A Shutter angle of 180 with a phase of -90 means that the shutter will be opened half a frame, centered around the current time