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Spray Brush is a painting tool that places objects in the scene view as you click or drag. On each stroke tick, it picks a random point inside the brush radius and attempts to place one object there. Placement is filtered by a Simple Filter (height, slope, fractal noise) and blocked by overlap checks. Unlike Advanced Brush, Spray Brush places one object per tick rather than filling a scatter pattern, and it uses SimpleTransformComponentSettings instead of the full Transform Components stack.
New to Spray Brush? Follow the step-by-step Spray Brush — Getting Started tutorial first.

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Supported resource types

Spray Brush supports:

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How placement works

On each stroke tick the tool:
  1. Picks a random point on the unit sphere projected onto the surface plane, multiplied by the brush radius. This gives a random offset from the brush center.
  2. Raycasts down to the surface at that offset point.
  3. Evaluates the Simple Filter at that hit point. If fitness is zero, the attempt is skipped.
  4. Selects a prototype from the active prototypes in the group using the weighted success values.
  5. Applies SimpleTransformComponentSettings to the instance.
  6. Runs the overlap check. If the instance overlaps an existing object, placement is skipped.
  7. If all checks pass, the object is placed and registered for undo.

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Tool-level settings

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Brush Settings

  • Brush Size — diameter of the brush area in world units. Default: 100. Use Shift + Scroll Wheel in the scene view to adjust.
  • Spacing — minimum cursor travel distance before the tool fires another placement attempt during a drag. Default: 30.

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Group-level settings

  • Simple Filter Settings — restricts placement by height, slope, and fractal noise. All enabled checks must pass for a placement to occur.

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Per-prototype settings

  • Success — weighted probability that this prototype is selected when the tool picks from the active prototypes. Prototypes with higher success values are chosen more often.
  • Overlap Check Settings — defines the overlap test applied before the object is placed. If the candidate instance overlaps an existing object, placement is cancelled.
  • Simple Transform Component Settings — the transform stack applied to each instance before placement. Provides basic position, rotation, and scale randomization.

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When to use Spray Brush

  • Fast manual scatter of objects over an area without configuring a full procedural system.
  • Placing one object type at a time with lightweight setup.
  • Situations where you want direct brush control with simple filters and no full transform stack.
Spray Brush places one object per stroke tick at a random offset within the radius. If you need deterministic scatter patterns, multiple objects per tick, terrain details, or terrain textures, use Advanced Brush instead.