Apply transform of first LOD to MeshAsset Instances

project/demo/assets/models/LODExample.tscn

@@ -1,18 +1,18 @@
 [gd_scene load_steps=11 format=3 uid="uid://bn5nf4esciwex"]
 
-[sub_resource type="StandardMaterial3D" id="StandardMaterial3D_788j8"]
-albedo_color = Color(1, 0, 0, 1)
-
-[sub_resource type="SphereMesh" id="SphereMesh_u4ac2"]
-material = SubResource("StandardMaterial3D_788j8")
-
 [sub_resource type="StandardMaterial3D" id="StandardMaterial3D_3i52q"]
 albedo_color = Color(1, 0.540167, 0.11, 1)
 
 [sub_resource type="BoxMesh" id="BoxMesh_xyuxq"]
 material = SubResource("StandardMaterial3D_3i52q")
 size = Vector3(0.85, 0.85, 0.85)
 
+[sub_resource type="StandardMaterial3D" id="StandardMaterial3D_788j8"]
+albedo_color = Color(1, 0, 0, 1)
+
+[sub_resource type="SphereMesh" id="SphereMesh_u4ac2"]
+material = SubResource("StandardMaterial3D_788j8")
+
 [sub_resource type="StandardMaterial3D" id="StandardMaterial3D_p0ha4"]
 albedo_color = Color(0.48, 1, 0.497333, 1)
 
@@ -38,14 +38,15 @@ cull_mode = 2
 [node name="TestMultimesh" type="Node3D"]
 
 [node name="Node3D" type="Node3D" parent="."]
+transform = Transform3D(0.707107, -0.707107, 0, 0.5, 0.5, -0.707107, 0.5, 0.5, 0.707107, 0, 0.725, 0.125)
 
 [node name="MeshInstance3D1" type="MeshInstance3D" parent="Node3D"]
-mesh = SubResource("SphereMesh_u4ac2")
+mesh = SubResource("BoxMesh_xyuxq")
 skeleton = NodePath("../..")
 
 [node name="MeshInstance3D2" type="MeshInstance3D" parent="Node3D"]
 visible = false
-mesh = SubResource("BoxMesh_xyuxq")
+mesh = SubResource("SphereMesh_u4ac2")
 skeleton = NodePath("../..")
 
 [node name="MeshInstance3D3" type="MeshInstance3D" parent="Node3D"]

project/demo/data/assets.tres

@@ -1,6 +1,7 @@
-[gd_resource type="Terrain3DAssets" load_steps=11 format=3 uid="uid://dal3jhw6241qg"]
+[gd_resource type="Terrain3DAssets" load_steps=13 format=3 uid="uid://dal3jhw6241qg"]
 
 [ext_resource type="PackedScene" uid="uid://bn5nf4esciwex" path="res://demo/assets/models/LODExample.tscn" id="1_4jrdu"]
+[ext_resource type="PackedScene" uid="uid://b1ronv2ln7dhb" path="res://plane.tscn" id="2_adagb"]
 [ext_resource type="Texture2D" uid="uid://c88j3oj0lf6om" path="res://demo/assets/textures/rock023_alb_ht.png" id="2_pog6b"]
 [ext_resource type="Texture2D" uid="uid://ddprscrpsofah" path="res://demo/assets/textures/ground037_alb_ht.png" id="3_g8f2m"]
 [ext_resource type="Texture2D" uid="uid://c307hdmos4gtm" path="res://demo/assets/textures/rock023_nrm_rgh.png" id="3_wncaf"]
@@ -21,6 +22,7 @@ name = "TextureCard"
 generated_type = 1
 height_offset = 0.5
 material_override = SubResource("StandardMaterial3D_b2vqk")
+generated_faces = 1
 last_lod = 0
 last_shadow_lod = 0
 lod0_range = 128.0
@@ -29,11 +31,18 @@ lod0_range = 128.0
 name = "LODExample"
 id = 1
 scene_file = ExtResource("1_4jrdu")
-height_offset = 0.5
 last_lod = 4
 last_shadow_lod = 4
 lod4_range = 256.0
 
+[sub_resource type="Terrain3DMeshAsset" id="Terrain3DMeshAsset_e6edf"]
+name = "plane"
+id = 2
+scene_file = ExtResource("2_adagb")
+last_lod = 0
+last_shadow_lod = 0
+lod0_range = 128.0
+
 [sub_resource type="Terrain3DTextureAsset" id="Terrain3DTextureAsset_lha57"]
 name = "Cliff"
 albedo_texture = ExtResource("2_pog6b")
@@ -54,5 +63,5 @@ ao_strength = 2.0
 detiling_rotation = 0.161
 
 [resource]
-mesh_list = Array[Terrain3DMeshAsset]([SubResource("Terrain3DMeshAsset_2qf8x"), SubResource("Terrain3DMeshAsset_y3ibi")])
+mesh_list = Array[Terrain3DMeshAsset]([SubResource("Terrain3DMeshAsset_2qf8x"), SubResource("Terrain3DMeshAsset_y3ibi"), SubResource("Terrain3DMeshAsset_e6edf")])
 texture_list = Array[Terrain3DTextureAsset]([SubResource("Terrain3DTextureAsset_lha57"), SubResource("Terrain3DTextureAsset_od0q7")])

project/plane.tscn

@@ -0,0 +1,18 @@
+[gd_scene load_steps=3 format=3 uid="uid://b1ronv2ln7dhb"]
+
+[sub_resource type="PlaneMesh" id="PlaneMesh_r8t2q"]
+
+[sub_resource type="StandardMaterial3D" id="StandardMaterial3D_s46f0"]
+cull_mode = 2
+albedo_color = Color(0.79, 0.972, 1, 1)
+
+[node name="root" type="Node3D"]
+
+[node name="Meshes" type="Node3D" parent="."]
+transform = Transform3D(1, 0, 0, 0, -4.37114e-08, -1, 0, 1, -4.37114e-08, 0, 0, 0)
+
+[node name="MeshInstance3D" type="MeshInstance3D" parent="Meshes"]
+transform = Transform3D(1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, -1)
+mesh = SubResource("PlaneMesh_r8t2q")
+skeleton = NodePath("../..")
+surface_material_override/0 = SubResource("StandardMaterial3D_s46f0")

src/terrain_3d_instancer.cpp

@@ -540,7 +540,8 @@ void Terrain3DInstancer::add_instances(const Vector3 &p_global_position, const D
 	TypedArray<Transform3D> xforms;
 	PackedColorArray colors;
 	for (int i = 0; i < count; i++) {
-		Transform3D t;
+		// Start with the mesh transform to correct the mesh to its visual state
+		Transform3D t = mesh_asset->get_mesh_transform();
 
 		// Get random XZ position and height in a circle
 		real_t r_radius = radius * sqrt(UtilityFunctions::randf());
@@ -556,45 +557,55 @@ void Terrain3DInstancer::add_instances(const Vector3 &p_global_position, const D
 		position.y = height_data[0];
 		bool raycast_hit = height_data[1];
 
-		// Orientation
-		Vector3 normal = Vector3(0.f, 1.f, 0.f);
+		// Orientation: Align the corrected mesh's up axis
+		Vector3 mesh_up = t.basis.get_column(1).normalized(); // Mesh's up axis after correction (typically Y)
 		if (align_to_normal) {
-			// Use either collision normal or terrain normal
-			normal = (on_collision && raycast_hit) ? (Vector3)height_data[2] : data->get_normal(position);
-			if (!normal.is_finite()) {
-				normal = Vector3(0.f, 1.f, 0.f);
-			} else {
+			Vector3 normal = (on_collision && raycast_hit) ? (Vector3)height_data[2] : data->get_normal(position);
+			if (normal.is_finite()) {
 				normal = normal.normalized();
-				Vector3 z_axis = Vector3(0.f, 0.f, 1.f);
-				Vector3 x_axis = -z_axis.cross(normal);
-				if (x_axis.length_squared() > 0.001) {
-					t.basis = Basis(x_axis, normal, z_axis).orthonormalized();
+				if (mesh_up.dot(normal) < 0.999f) { // Avoid rotation if already aligned
+					Quaternion rotation = Quaternion(mesh_up, normal);
+					t.basis = Basis(rotation) * t.basis;
 				}
 			}
+		} else {
+			// Align mesh's up axis to global Y when not aligning to normal
+			if (mesh_up.dot(Vector3(0, 1, 0)) < 0.999f) {
+				Quaternion rotation = Quaternion(mesh_up, Vector3(0, 1, 0));
+				t.basis = Basis(rotation) * t.basis;
+			}
 		}
+
+		// Apply spin around the current up axis (global Y if align_to_normal is false)
 		real_t spin = (fixed_spin + random_spin * UtilityFunctions::randf()) * Math_PI / 180.f;
 		if (abs(spin) > 0.001f) {
-			t.basis = t.basis.rotated(normal, spin);
+			t.basis = t.basis.rotated(t.basis.get_column(1), spin);
 		}
+
+		// Apply tilt around the post-transform X-axis
 		real_t tilt = (fixed_tilt + random_tilt * (2.f * UtilityFunctions::randf() - 1.f)) * Math_PI / 180.f;
 		if (abs(tilt) > 0.001f) {
-			t.basis = t.basis.rotated(t.basis.get_column(0), tilt); // Rotate pitch, X-axis
+			t.basis = t.basis.rotated(t.basis.get_column(0), tilt);
 		}
 
-		// Scale
+		// Apply scale
 		real_t t_scale = CLAMP(fixed_scale + random_scale * (2.f * UtilityFunctions::randf() - 1.f), 0.01f, 10.f);
 		t = t.scaled(Vector3(t_scale, t_scale, t_scale));
 
-		// Position. mesh_asset height offset added in add_transforms
+		// Apply editor height offset along the post-transform up axis
 		real_t offset = height_offset + random_height * (2.f * UtilityFunctions::randf() - 1.f);
-		position += t.basis.get_column(1) * offset; // Offset along UP axis
-		t = t.translated(position);
+		position += t.basis.get_column(1) * offset;
+
+		// Set the final position
+		t.origin = position;
 
 		// Color
 		Color col = vertex_color;
 		col.set_v(CLAMP(col.get_v() - random_darken * UtilityFunctions::randf(), 0.f, 1.f));
 		col.set_h(fmod(col.get_h() + random_hue * (2.f * UtilityFunctions::randf() - 1.f), 1.f));
 
+		t *= mesh_asset->get_mesh_transform(); // Apply mesh asset transform
+
 		xforms.push_back(t);
 		colors.push_back(col);
 	}
@@ -713,9 +724,11 @@ void Terrain3DInstancer::remove_instances(const Vector3 &p_global_position, cons
 					// Use localised ring center
 					real_t radial_distance = localised_ring_center.distance_to(Vector2(t.origin.x, t.origin.z));
 					Vector3 height_offset = t.basis.get_column(1) * mesh_height_offset;
+
+					Vector3 base_position = t.origin + global_local_offset - height_offset;
 					if (radial_distance < radius &&
 							UtilityFunctions::randf() < CLAMP(0.175f * strength, 0.005f, 10.f) &&
-							data->is_in_slope(t.origin + global_local_offset - height_offset, slope_range, invert)) {
+							data->is_in_slope(base_position, slope_range, invert)) {
 						_backup_region(region);
 						continue;
 					} else {
@@ -776,7 +789,10 @@ void Terrain3DInstancer::add_transforms(const int p_mesh_id, const TypedArray<Tr
 	for (int i = 0; i < p_xforms.size(); i++) {
 		// Get adjusted xform/color
 		Transform3D trns = p_xforms[i];
-		trns.origin += trns.basis.get_column(1) * mesh_asset->get_height_offset(); // Offset along UP axis
+		// Apply the mesh transform first
+		trns = mesh_asset->get_mesh_transform() * trns;
+		// Then apply the height offset along the transformed up axis
+		trns.origin += trns.basis.get_column(1) * mesh_asset->get_height_offset();
 		Color col = COLOR_WHITE;
 		if (p_colors.size() > i) {
 			col = p_colors[i];
@@ -970,15 +986,19 @@ void Terrain3DInstancer::update_transforms(const AABB &p_aabb) {
 					Transform3D t = xforms[i];
 					Vector3 global_origin(t.origin + global_local_offset);
 					if (rect.has_point(Vector2(global_origin.x, global_origin.z))) {
-						Vector3 height_offset = t.basis.get_column(1) * mesh_height_offset;
-						t.origin -= height_offset;
-						Array height_data = _get_usable_height(global_origin, Vector2(0.f, 90.f), false, on_collision);
+						// Get the instance's up axis from its basis (post-transform)
+						Vector3 up_axis = t.basis.get_column(1).normalized();
+						// Calculate the base position by moving down along the up axis by height_offset
+						Vector3 base_position = global_origin - up_axis * mesh_height_offset;
+						// Get the new terrain height at the base position
+						Array height_data = _get_usable_height(base_position, Vector2(0.f, 90.f), false, on_collision);
 						if (height_data.size() != 3) {
 							continue;
 						}
-						t.origin.y = height_data[0];
-
-						t.origin += height_offset;
+						real_t new_terrain_height = height_data[0];
+						// Adjust the instance’s position so its base matches the new terrain height
+						Vector3 adjustment = up_axis * (new_terrain_height - base_position.y);
+						t.origin += adjustment;
 					}
 					updated_xforms.push_back(t);
 					updated_colors.push_back(colors[i]);

src/terrain_3d_mesh_asset.cpp

@@ -210,6 +210,26 @@ void Terrain3DMeshAsset::set_scene_file(const Ref<PackedScene> &p_scene_file) {
 		// Now process the meshes
 		for (int i = 0, count = MIN(mesh_instances.size(), MAX_LOD_COUNT); i < count; i++) {
 			MeshInstance3D *mi = cast_to<MeshInstance3D>(mesh_instances[i]);
+			// Store the transforms of LOD0 up to the scene root
+			if (i == 0) {
+				_mesh_transform = Transform3D(); // Reset to identity
+				Vector<Transform3D> transforms;
+				Node *current = mi;
+				while (current) {
+					Node3D *n = cast_to<Node3D>(current);
+					if (n) {
+						transforms.push_back(n->get_transform());
+					}
+					if (current == node) {
+						break; // Stop at the scene root
+					}
+					current = current->get_parent();
+				}
+				// Apply transforms from root to mesh (left to right)
+				for (int i = transforms.size() - 1; i >= 0; i--) {
+					_mesh_transform = _mesh_transform * transforms[i];
+				}
+			}
 			LOG(DEBUG, "Found mesh: ", mi->get_name());
 			if (_name == "New Mesh") {
 				_name = _packed_scene->get_path().get_file().get_basename();

src/terrain_3d_mesh_asset.h

@@ -55,6 +55,7 @@ class Terrain3DMeshAsset : public Terrain3DAssetResource {
 
 	// Working data
 	TypedArray<Mesh> _meshes;
+	Transform3D _mesh_transform = Transform3D();
 	Ref<Texture2D> _thumbnail;
 
 	void _clear_lod_ranges();
@@ -79,6 +80,7 @@ class Terrain3DMeshAsset : public Terrain3DAssetResource {
 	void set_generated_type(const GenType p_type);
 	GenType get_generated_type() const { return _generated_type; }
 	Ref<Mesh> get_mesh(const int p_lod = 0) const;
+	Transform3D get_mesh_transform() const { return _mesh_transform; }
 	Ref<Texture2D> get_thumbnail() const { return _thumbnail; }
 	void set_height_offset(const real_t p_offset);
 	real_t get_height_offset() const { return _height_offset; }