Bring the diamond island into main.tscn with region-border props

Promote debug/HexDiamondIsland.gd to terrain.gd at project root now
that main.tscn depends on it, and swap it in for the old flat
checkerboard Ground (Player/Camera/POI untouched, table sits at the
same y=0 the old ground surface used).

Add _build_region_borders(): places mountain.glb/mountain2v5.glb/
forest.glb (same models, scale factors and hitbox sizes already used
elsewhere in main.tscn) continuously along the 6 ridges between table
corners and girdle corners, i.e. the shared edges between adjacent
outer regions.

debug/hex_diamond_island.tscn

@@ -1,7 +1,7 @@
 [gd_scene format=3]
 
 [ext_resource type="Script" uid="uid://bia8axed2ndwj" path="res://debug/FreeCam.gd" id="1_freecam"]
-[ext_resource type="Script" path="res://debug/HexDiamondIsland.gd" id="2_hexdi"]
+[ext_resource type="Script" uid="uid://cpo34pbk0145n" path="res://terrain.gd" id="2_hexdi"]
 
 [sub_resource type="Environment" id="Environment_hexdi"]
 background_mode = 1

main.tscn

@@ -1,7 +1,7 @@
 [gd_scene format=3 uid="uid://bju1lndv8l1mo"]
 
 [ext_resource type="Script" uid="uid://ckrqvbqw08kin" path="res://player.gd" id="1_0xm2m"]
-[ext_resource type="Texture2D" uid="uid://c3ajv7vb8c4fb" path="res://assets/debug/checkerboard.png" id="1_1bvp3"]
+[ext_resource type="Script" uid="uid://cpo34pbk0145n" path="res://terrain.gd" id="1_terrain"]
 [ext_resource type="Texture2D" uid="uid://epcqli428yem" path="res://assets/sprites/player/debug_player.png" id="2_h2yge"]
 [ext_resource type="Script" uid="uid://b0y06y7c0bihj" path="res://camera_rig.gd" id="3_h2yge"]
 [ext_resource type="PackedScene" uid="uid://be6ufrc3dsjge" path="res://poi.tscn" id="5_lquwl"]
@@ -13,22 +13,6 @@
 ambient_light_color = Color(0, 0, 0.31764707, 1)
 ambient_light_energy = 0.3
 
-[sub_resource type="StandardMaterial3D" id="StandardMaterial3D_lquwl"]
-albedo_texture = ExtResource("1_1bvp3")
-
-[sub_resource type="CylinderMesh" id="CylinderMesh_lquwl"]
-top_radius = 100.0
-bottom_radius = 100.0
-height = 0.2
-
-[sub_resource type="StandardMaterial3D" id="StandardMaterial3D_h2yge"]
-shading_mode = 0
-albedo_color = Color(0, 0.32156864, 0, 1)
-
-[sub_resource type="CylinderShape3D" id="CylinderShape3D_lquwl"]
-height = 0.2
-radius = 100.0
-
 [sub_resource type="CylinderShape3D" id="CylinderShape3D_7mycd"]
 height = 0.5
 radius = 0.16
@@ -189,17 +173,8 @@ environment = SubResource("Environment_h2yge")
 
 [node name="DirectionalLight3D" type="DirectionalLight3D" parent="." unique_id=630943989]
 
-[node name="Ground" type="StaticBody3D" parent="." unique_id=309197966]
+[node name="Terrain" type="Node3D" parent="." unique_id=309197966]
-
+script = ExtResource("1_terrain")
-[node name="MeshInstance3D" type="MeshInstance3D" parent="Ground" unique_id=479475733]
-transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0.00084638596, -0.2, -0.001806736)
-material_override = SubResource("StandardMaterial3D_lquwl")
-mesh = SubResource("CylinderMesh_lquwl")
-surface_material_override/0 = SubResource("StandardMaterial3D_h2yge")
-
-[node name="CollisionShape3D" type="CollisionShape3D" parent="Ground" unique_id=1301061872]
-transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, -0.2, 0)
-shape = SubResource("CylinderShape3D_lquwl")
 
 [node name="Player" type="CharacterBody3D" parent="." unique_id=1504574304 groups=["player"]]
 transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0.25, 0)

terrain.gd

@@ -12,14 +12,27 @@ extends Node3D
 @export var pavilion_depth  : float = 190.0   # Höhenabfall Rundiste -> Spitze
 @export var angle_offset_deg: float = 0.0
 
+@export var border_spacing : float = 18.0   # Abstand zwischen Grenz-Props entlang eines Grats
+@export var border_jitter  : float = 3.0    # zufälliger seitlicher Versatz
+
 const COLOR_TABLE    := Color(0.75, 0.74, 0.70)
 const COLOR_FACET_A  := Color(0.55, 0.55, 0.48)
 const COLOR_FACET_B  := Color(0.49, 0.49, 0.43)
 const COLOR_PAVILION := Color(0.30, 0.28, 0.26)
 
+# Grenz-Props: gleiche Modelle + Skalierung + Hitbox-Maße wie in main.tscn
+const MOUNTAIN_SCENE  := preload("res://assets/models/mountain.glb")
+const MOUNTAIN2_SCENE := preload("res://assets/models/mountain2v5.glb")
+const FOREST_SCENE    := preload("res://assets/models/forest.glb")
+
+const MOUNTAIN_SCALE  := 0.1
+const MOUNTAIN2_SCALE := 0.05
+const FOREST_SCALE    := 0.2
+
 func _ready() -> void:
 	_build_crown()
 	_build_pavilion()
+	_build_region_borders()
 
 func _hex_angle(k: int) -> float:
 	return deg_to_rad(angle_offset_deg) + float(k) / 6.0 * TAU
@@ -103,3 +116,66 @@ func _build_pavilion() -> void:
 	mi.name = "Pavilion"
 	mi.mesh = mesh
 	add_child(mi)
+
+# ═══════════════════════════════════════════════
+# GRENZEN — Berg/Wald entlang der 6 Grate zwischen den Regionen
+# Grat k = Strecke von Tisch-Ecke T[k] zu Rundiste-Ecke G[k]
+# (gemeinsame Kante von Facette k-1 und Facette k)
+# ═══════════════════════════════════════════════
+func _build_region_borders() -> void:
+	var borders := Node3D.new()
+	borders.name = "Borders"
+	add_child(borders)
+
+	for k in range(6):
+		var a := _hex_angle(k)
+		var dir := Vector3(cos(a), 0.0, sin(a))
+		var perp := Vector3(-dir.z, 0.0, dir.x)
+
+		var t := table_radius
+		while t <= girdle_radius:
+			var frac := (t - table_radius) / (girdle_radius - table_radius)
+			var pos := dir * t
+			pos.y = lerp(0.0, -crown_drop, frac)
+			pos += perp * randf_range(-border_jitter, border_jitter)
+
+			_place_border_prop(borders, pos)
+			t += border_spacing + randf_range(-4.0, 4.0)
+
+func _place_border_prop(parent: Node3D, pos: Vector3) -> void:
+	var roll := randf()
+	var inst: Node3D
+	var scale_factor: float
+	var shape: Shape3D
+
+	if roll < 0.4:
+		inst = MOUNTAIN_SCENE.instantiate() as Node3D
+		scale_factor = MOUNTAIN_SCALE
+		var cap := CapsuleShape3D.new()
+		cap.radius = 7.0
+		cap.height = 20.0
+		shape = cap
+	elif roll < 0.7:
+		inst = MOUNTAIN2_SCENE.instantiate() as Node3D
+		scale_factor = MOUNTAIN2_SCALE
+		var cap2 := CapsuleShape3D.new()
+		cap2.radius = 8.5078125
+		cap2.height = 17.015625
+		shape = cap2
+	else:
+		inst = FOREST_SCENE.instantiate() as Node3D
+		scale_factor = FOREST_SCALE
+		var cyl := CylinderShape3D.new()
+		cyl.radius = 0.72021484
+		cyl.height = 2.2817383
+		shape = cyl
+
+	inst.position = pos
+	inst.rotation.y = randf() * TAU
+	inst.scale = Vector3.ONE * scale_factor
+
+	var cs := CollisionShape3D.new()
+	cs.shape = shape
+	inst.add_child(cs)
+
+	parent.add_child(inst)

terrain.gd.uid

@@ -0,0 +1 @@
+uid://cpo34pbk0145n