Surface Scattering Tab

Distribution mode – Allows selecting between different distribution modes.

Random – Scatters randomly on all mesh and closed spline distribution objects.
Uv – Uses the distribution objects' UVW mapping to scatter the instances in regular patterns.

Count – Defines an exact number of instances to scatter overall. When the Per square option is enabled, scatters instances per area, defined by density. The number is always limited by the Config Max. limit option.

Per square – When enabled, the number of instances to scatter is defined by density (Count per square having the given edge length). The number of instances is always limited by the Config Max. limit option. The specified value is the edge length of a square, which defines an area for computing the scatter density.

Pattern – Allows to select between different distribution patterns. Click on the arrow next to the pattern selector () to preview the pattern layouts.

None – No map is selected.
Custom map – Uses a custom map.
Distorted streaks high/low – Distorted streaks pattern with different densities. 
Groups high/low – Groups pattern with different densities. 
Fractal patches high/low – Fractal patches pattern with different densities. 
Straight lines high/low – Straight lines pattern with different densities. 
Stretched patches high/low – Stretched lines pattern with different densities. 

Distribution – Specifies a texture map or shader used for instance distribution. White areas of the texture are treated as maximum density, and black areas are treated as areas with no instances.

Pattern – Allows to select between different distribution patterns. Click on the arrow next to the pattern selector () to preview the pattern layouts.

None – No map is selected.
Custom map – Uses a custom map.
Distorted streaks high/low – Distorted streaks pattern with different densities. 
Groups high/low – Groups pattern with different densities. 
Fractal patches high/low – Fractal patches pattern with different densities. 
Straight lines high/low – Straight lines pattern with different densities. 
Stretched patches high/low – Stretched lines pattern with different densities. 

Use planar mapping – When enabled, simple planar UVW mapping is applied to the distribution object and used instead of its existing UVW channel.

Spacing U – Scales the pattern in the U axis - 100% spacing makes the pattern occupy the whole 0-1 UV space; with 50% spacing, the pattern gets repeated 2 times in U.

Spacing V – Scales the pattern in the V axis - 100% spacing makes the pattern occupy the whole 0-1 UV space; with 50% spacing, the pattern gets repeated 2 times in V.

Jitter U – Randomly jitters each instance in the U axis, with 0% being entirely deterministic placement (no jitter) and 100% being entirely random placement.

Jitter V – Randomly jitters each instance in the V axis, with 0% being entirely deterministic placement (no jitter) and 100% being entirely random placement.

Offset U – Offsets the pattern in the U axis. Each 100% added or subtracted moves the pattern by one entire repetition - which means that, e.g., 0% and 100% offsets yield the same result.

Offset V – Offsets the pattern in the V axis. Each 100% added or subtracted moves the pattern by one entire repetition - which means that, e.g., 0% and 100% offsets yield the same result.

Lock V – Locks the V coordinate for Spacing, Jitter, and Offset to the same value as the U coordinate.

Edge Trimming – Enables the use of an Edge Trimming texture.

Enabled – Toggles the slope parameter on and off. Slope allows scattered geometry to be removed based on the angle of the underlying geometry. If an area is outside the range defined in this rollout, geometry is removed from it. This is great for realistically simulating steep mountains, as there is no greenery on the steepest slopes.

Up mode – Allows selecting between different modes for the up axis. See the Slope Up mode example.

Local – The up vector of each individual distribute-on object is used to define the slope limitation.
World – The world Y-axis up vector is used for all distribute-on objects to define the slope limitation.

From/To – These values set the range of angles, measured in degrees, between either the Local or the World up vector and the surface normal. Determines how steep the surface can be before instances are filtered out. Instances scattered outside of this range are erased. See the Slope example.

Enabled – Toggles the altitude parameter on and off. Altitude defines a height range (in cm) for the scattered geometry to distribute on. Any geometry outside the range is filtered out. See the example for more.

Coord. space – Determines whether Local or World coordinate space is used for the height range.

From/To – Defines the minimum and maximum height of the range. Any geometry below or above this is filtered out.

Falloff – Smooths out the altitude cutoff, allowing for a gradual fade-out. Use the curve control to define the transition. For further controls, open the menu. Additional points can be added by holding Ctrl and left-clicking anywhere on the curve. See the example or more.