Filters

Filters allow you to discard some instances based on a set of parameters. There are Altitude filter, Slope filter, Collision filter, Boundary filter, and Camera filter.

Boundaries filter

The Boundaries filter controls the density and the scale of scattered instances depending on their distance to the boundaries of surfaces and masks.

Parameter	Description
Offset	Distance to the boundary under which all instances are discarded.
Falloff	Length of the falloff that interpolates scale and density near the boundaries. Learn how to use the falloff curve in the Falloff Curves section.
Boundary check	How Skatter determines if an instance is inside of the boundaries or not. With Object origin, only the axes of the instance need to be inside the boundaries. Some instances will probably overlap with the boundaries. With Object radius, the whole shape of the object is considered to determine if the instance lies inside the boundaries. It guarantees that the instances will not overlap with the boundaries.

Altitude filter

The Altitude filter controls the density and the scale of scattered instances depending on their absolute vertical positions in the model. For instance, this can be useful to control scattering over mountainous landscapes or to finely tune positioning over green walls.

Parameter	Description
Top	Height beyond which all instances are discarded
Top falloff	Length of the falloff that interpolates scale and density near the top
Bottom	Height below which all instances are discarded
Bottom falloff	Length of the falloff that interpolates scale and density near the bottom

If Top falloff or Bottom falloff have positive values, an advanced curve editor appears to customize the evolution of density and scale. Learn how to use that curve editor in the Falloff Curves section.

Slope filter

The Slope filter controls the density and the scale of scattered instances depending on the angle of the surfaces on which they are placed. For example, it can be used to prevent trees from being scattered on a cliff.

Parameter	Description
Max	Angle beyond which all instances are discarded.
Max falloff	Angle of the falloff that interpolates scale and density near the max angle.
Min	Angle below which all instances are discarded.
Min falloff	Angle of the falloff that interpolates scale and density near the min angle.

If Max falloff or Min falloff have positive values, an advanced curve editor appears to customize the evolution of density and scale. Learn how to use that curve editor in the Falloff Curves section.

Collision filter

The Collision filter discards scattered instances that overlap with each other, to prevent unrealistic interpenetrations between objects.

Parameter	Description
Radius	Percentage of the actual object's size used for checking collisions

Contrary to the Scale multiplier parameter of objects, the Radius parameter has no effect on the final size of the instances. It only changes the size used internally by Skatter when checking collisions.

This is useful in cases when instances should be spaced generously (> 100%) or to allow a certain degree of interpenetration (< 100%).

Falloff curves

All falloffs in Skatter are controlled by a falloff curve. By default, falloffs are interpolated linearly, but you can draw your own curve to create sophisticated effects.

Move your cursor over the curve preview, and click the icon to edit the curve. You can also click the icon to reset the curve to its default linear state, and the icon to invert the curve.