Emit from image
Last updated
Emit from image is a Generate effect.
What it does
Section titled “What it does”This keeps points that land on something bright.
One limit, the same as Scatter: because these points depend on a picture, neither Points sample or Layer points can read the stream. Wiring one of this layer’s own consumers to it works.
Parameters
Section titled “Parameters”| Parameter | Control | Range | Default | Unit |
|---|---|---|---|---|
| Source layer | Layer | Any layer in the composition | None | - |
| Threshold | Slider | 0 to 100 | 50 | Per cent |
| Density | Slider | 0 to 100; higher | 20 | - |
| Seed | Seed | Any whole number | A fresh random seed per instance | - |
| 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 | - |
| 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, Threshold, Density, Seed.
- 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.
- 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.
Related
Section titled “Related”- Scatter - the same throw, kept where a layer is opaque.
- Grid
- Clone to points
- The node graph - where the Points socket is wired.
- Generate
- Effects