Masks

Masks are entities that control where instances can and cannot be scattered. They can either be Paint masks, Area masks, Path masks, Image masks, or Composition masks.

If a composition contains both types of masks, inclusive masks are applied first and then exclusive masks are applied over the remaining instances.

Masks are automatically reordered when toggling their inclusive/exclusive mode in order to reflect this rule.

Paint masks

A Paint mask allows you to manually draw the shape of the mask. You draw the shape with a brush, just like you would in Photoshop or similar image editors.

Erasing an inclusive Paint mask is not the same thing as drawing an exclusive Paint mask!

Area masks

An Area mask is a group or a component instance that defines a space under which instances will not be scattered.

Path masks

A Path mask uses a curve with a configurable thickness under which instances will not be scattered.

Image masks

An Image mask uses an external image file to control where instances can be scattered. This is useful to reproduce complex patterns.

Image masks rely on the surface hosts having valid texture coordinates. Please make sure that your surface hosts are properly set up.

SketchUp only allows extensions to draw textures in the viewport since SketchUp 2020 so the preview will not be available for older versions.

Darkness values

The whiter a pixel of the image is, the more likely it is for an instance to be scattered there.

A 100% white pixel means that instances can be scattered there. A 100% black pixel means that instances cannot be scattered there. Values in between are interpolated linearly.

Image masks only consider grayscale values, as shown in the SketchUp preview. Skatter accepts colored images and converts them to grayscale.

Composition masks

A Composition mask uses the instances from another composition to filter where instances can and cannot be scattered.

For instance, a composition Trees might be used as the composition mask for a composition Fallen leaves, so that they only appear around the trees.

It is possible to chain multiple compositions as masks of each other ("composition A masks composition B which itself masks composition C...").

However, Skatter does not allow to create cycles where all compositions depend on each other ("A → B → C → A") as it would be impossible to compute.

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