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Before starting this tutorial, read:
The Brush Erase tool removes already-placed objects and terrain details from the scene using a brush. It does not erase uniformly — each object passes through a probability check based on brush mask alpha, filter fitness, Erase Strength, and a per-prototype success value. This lets you erase softly or leave some objects in place by chance.

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Step 1 — Open the MegaWorld Window and select Brush Erase

Press Alt + Z to open the MegaWorld Window. In the Tools Panel, click the + button and choose Brush Erase.

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Step 2 — Select the prototypes you want to erase

In the Selection Panel, select the group and enable the prototypes you want to remove. Only selected and active prototypes are affected. Uncheck a prototype to protect it from erasure without removing it from the list.

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Step 3 — Adjust brush size and erase strength

In the Settings Panel:
  • Set Brush Size to control the erase diameter. You can also hold Shift and scroll the mouse wheel in the Scene View.
  • Set Erase Strength (range 0 to 1) to control the overall erase probability. At 1, objects are erased based on filter fitness and brush mask alone. Lower values reduce how many objects are removed on each pass.

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Step 4 — Optionally restrict erasure with filters

In the group’s Filter Settings, you can enable Simple Filter or Mask Filter to limit which objects are eligible for erasure. For example, a slope filter restricts erasure to objects on slopes within a defined angle range — objects on other terrain are skipped. For Terrain Detail groups, the Mask Filter modulates detail density reduction across the brush area rather than filtering discrete objects.

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Step 5 — Optionally adjust per-prototype erase probability

Each prototype has an Additional Erase Settings section with a Success of Erase (%) field. At 100 (the default), every object that passes the main check is erased. Lower this value to leave some objects in place randomly on each pass.

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Step 6 — Erase in the Scene View

Move your cursor into the Scene View and click or drag to erase. The tool fires on mouse down and continues as you drag, respecting the brush Spacing setting.

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What’s next

  • Use Mask Filters to erase only within a specific height or slope range.
  • Use Brush Modify if you want to adjust objects rather than delete them.
  • Use Edit to remove individual objects one by one.
  • Read the full Brush Erase reference documentation.