Reference / Effects / Generate
Updated
Emit from image
Emit from image is a Generate effect.
What it does
Section titled “What it does”This keeps points that land on something bright.
These points depend on a picture, as Scatter’s do. The points effects below it in the same layer’s stack can read them. Points sample cannot, and neither can Layer points from another layer. A Bake points below it makes its points readable by both.
Parameters
Section titled “Parameters”| Parameter | Control | Range | Default | Unit |
|---|---|---|---|---|
| Source layer | Layer | Any layer in the composition | None | - |
| Map placement | Dropdown | As placed in comp · Stretch to fit · Centre | As placed in comp | - |
| Threshold | Slider | 0 to 100 | 50 | Per cent |
| Density | Slider | 0 to 100; higher | 20 | - |
| Size | Slider | 0 to 200; higher | 6 | Pixels at composition size |
| Feather | Slider | 0 to 100 | 100 | Per cent |
| Colour | Colour | Each channel 0 to 4, scene-linear | 1, 1, 1, 1 | - |
| Max points | Slider, whole numbers | 1 to 200000; up to 1000000 | 20000 | - |
| Seed | Seed | Any whole number | A fresh random seed per instance | - |
| Mix | Slider | 0 to 100 | 100 | Per cent |
| Blend | Dropdown | Normal · Darken · Multiply · Colour burn · Linear burn · Darker colour · Add · Lighten · Screen · Colour dodge · Lighter colour · Overlay · Soft light · Hard light · Linear light · Vivid light · Pin light · Hard mix · Difference · Exclusion · Subtract · Divide · Hue · Saturation · Colour · Luminosity | Normal | - |
| Matte | Layer | Any layer in the composition | None | - |
| Invert | Checkbox | On or off | Off | - |
| Channel | Dropdown | Luminance · Alpha · Red · Green · Blue | Luminance | - |
In the Effect Controls panel:
- Source groups Source layer, Map placement, Threshold, Density.
- Point groups Size, Feather, Colour, Max points.
- Matte is an input to an effect, scaling the strength. Invert inverts the mattes for calculating strength.
What each control does
Section titled “What each control does”- Source layer: the layer whose brightness decides where the points go. Nothing is emitted until you set it.
- Map placement: where the Source layer’s picture sits on this layer. As placed in comp reads it where that layer sits in the composition. Stretch to fit stretches it over this layer. Centre centres it at its own size. An effect saved before this row existed stays on Stretch to fit.
- Threshold: where “bright” starts. Below it nothing is kept. At white everything is.
- Density: how many points are thrown per hundred-pixel square of the composition, so the same number means the same spacing whatever size the composition is.
- Seed: which points. Reseeding moves the crowd and changes which of it survives.
- Size: the diameter of the disc a point is drawn as.
- Feather: how soft that disc’s edge is. At nought it is a hard circle.
- Colour: what the points are drawn in. Values above 1 are legal, and useful under a Glow.
- Max points: the most points that may be thrown. A ceiling on the work rather than on the look, since only some of them stand. It does not animate.
- Mix: how much of the drawing lands on the picture. At nought the points are still emitted on the socket.
- Matte and Invert drive the strength of the effect from another layer’s brightness. See Effects.