diff --git a/src/svmap/terrain_field.gd b/src/svmap/terrain_field.gd
index bbf9722..0b226cc 100644
--- a/src/svmap/terrain_field.gd
+++ b/src/svmap/terrain_field.gd
@@ -82,6 +82,7 @@ static func apply_brush(heights: PackedFloat32Array, res: int, size_x: float, si
 				heights[idx] = nh
 				changed = true
 			x += 1
+		z += 1
 	return changed