diff --git a/src/models/Document.zig b/src/models/Document.zig
index 4deb110..c3a8157 100644
--- a/src/models/Document.zig
+++ b/src/models/Document.zig
@@ -4,7 +4,7 @@ const Size = basic_models.Size;
 const Document = @This();
 
 pub const Object = @import("Object.zig");
-const shape = @import("shape.zig");
+const shape = @import("shape/shape.zig");
 
 size: Size,
 allocator: std.mem.Allocator,
diff --git a/src/models/shape/arc.zig b/src/models/shape/arc.zig
index f9fe54f..ef5a793 100644
--- a/src/models/shape/arc.zig
+++ b/src/models/shape/arc.zig
@@ -2,6 +2,7 @@ const std = @import("std");
 const Object = @import("../Object.zig");
 const PropertyData = @import("../Property.zig").Data;
 const Rect = @import("../basic_models.zig").Rect;
+const shape_mod = @import("shape.zig");
 
 /// Теги обязательных свойств (заглушка: arc пока не реализован).
 pub fn getRequiredTags() []const std.meta.Tag(PropertyData) {
@@ -15,7 +16,8 @@ pub fn appendDefaultShapeProperties(allocator: std.mem.Allocator, obj: *Object)
     return error.ArcNotImplemented;
 }
 
-/// Локальные границы дуги (заглушка: возвращает null).
-pub fn getLocalBounds(_: *const Object) ?Rect {
-    return null;
+/// Локальные границы дуги (заглушка: пока не реализовано).
+pub fn getLocalBounds(obj: *const Object) !Rect {
+    try shape_mod.ensure(obj, .arc);
+    return error.ArcNotImplemented;
 }
diff --git a/src/models/shape/broken.zig b/src/models/shape/broken.zig
index 80ad026..7fce53d 100644
--- a/src/models/shape/broken.zig
+++ b/src/models/shape/broken.zig
@@ -4,6 +4,7 @@ const Property = @import("../Property.zig").Property;
 const PropertyData = @import("../Property.zig").Data;
 const Point2 = @import("../basic_models.zig").Point2;
 const Rect = @import("../basic_models.zig").Rect;
+const shape_mod = @import("shape.zig");
 
 /// Точки ломаной по умолчанию (для создания).
 pub const default_points = [_]Point2{
@@ -24,10 +25,11 @@ pub fn appendDefaultShapeProperties(allocator: std.mem.Allocator, obj: *Object)
     try obj.properties.append(allocator, .{ .data = .{ .points = points } });
 }
 
-/// Локальные границы ломаной: AABB по всем точкам. Возвращает null, если точек нет.
-pub fn getLocalBounds(obj: *const Object) ?Rect {
-    const p = obj.getProperty(.points) orelse return null;
-    if (p.points.items.len == 0) return null;
+/// Локальные границы ломаной: AABB по всем точкам.
+pub fn getLocalBounds(obj: *const Object) !Rect {
+    try shape_mod.ensure(obj, .broken);
+    const p = obj.getProperty(.points).?;
+    if (p.points.items.len == 0) return error.EmptyPoints;
     var min_x: f32 = p.points.items[0].x;
     var max_x: f32 = min_x;
     var min_y: f32 = p.points.items[0].y;
diff --git a/src/models/shape/ellipse.zig b/src/models/shape/ellipse.zig
index b3da3ce..23293df 100644
--- a/src/models/shape/ellipse.zig
+++ b/src/models/shape/ellipse.zig
@@ -3,6 +3,7 @@ const Object = @import("../Object.zig");
 const Property = @import("../Property.zig").Property;
 const PropertyData = @import("../Property.zig").Data;
 const Rect = @import("../basic_models.zig").Rect;
+const shape_mod = @import("shape.zig");
 
 /// Свойства фигуры по умолчанию (для создания и проверки типа). Теги для ensure выводятся отсюда.
 pub const default_shape_properties = [_]Property{
@@ -20,8 +21,9 @@ pub fn appendDefaultShapeProperties(allocator: std.mem.Allocator, obj: *Object)
 }
 
 /// Локальные границы эллипса: [-radii.x, -radii.y] .. [radii.x, radii.y].
-pub fn getLocalBounds(obj: *const Object) ?Rect {
-    const r = obj.getProperty(.radii) orelse return null;
+pub fn getLocalBounds(obj: *const Object) !Rect {
+    try shape_mod.ensure(obj, .ellipse);
+    const r = obj.getProperty(.radii).?;
     return .{
         .x = -r.radii.x,
         .y = -r.radii.y,
diff --git a/src/models/shape/line.zig b/src/models/shape/line.zig
index a01fe33..649aa4d 100644
--- a/src/models/shape/line.zig
+++ b/src/models/shape/line.zig
@@ -3,6 +3,7 @@ const Object = @import("../Object.zig");
 const Property = @import("../Property.zig").Property;
 const PropertyData = @import("../Property.zig").Data;
 const Rect = @import("../basic_models.zig").Rect;
+const shape_mod = @import("shape.zig");
 
 /// Свойства фигуры по умолчанию (для создания и проверки типа). Теги для ensure выводятся отсюда.
 pub const default_shape_properties = [_]Property{
@@ -20,8 +21,9 @@ pub fn appendDefaultShapeProperties(allocator: std.mem.Allocator, obj: *Object)
 }
 
 /// Локальные границы линии: от (0,0) до end_point.
-pub fn getLocalBounds(obj: *const Object) ?Rect {
-    const ep = obj.getProperty(.end_point) orelse return null;
+pub fn getLocalBounds(obj: *const Object) !Rect {
+    try shape_mod.ensure(obj, .line);
+    const ep = obj.getProperty(.end_point).?;
     const min_x = @min(0, ep.end_point.x);
     const max_x = @max(0, ep.end_point.x);
     const min_y = @min(0, ep.end_point.y);
diff --git a/src/models/shape.zig b/src/models/shape/shape.zig
similarity index 64%
rename from src/models/shape.zig
rename to src/models/shape/shape.zig
index 2a14894..8762102 100644
--- a/src/models/shape.zig
+++ b/src/models/shape/shape.zig
@@ -1,13 +1,13 @@
 const std = @import("std");
-const Object = @import("Object.zig");
-const Property = @import("Property.zig").Property;
-const PropertyData = @import("Property.zig").Data;
-const defaultCommonProperties = @import("Property.zig").defaultCommonProperties;
-const basic_models = @import("basic_models.zig");
-const line = @import("shape/line.zig");
-const ellipse = @import("shape/ellipse.zig");
-const broken = @import("shape/broken.zig");
-const arc = @import("shape/arc.zig");
+const Object = @import("../Object.zig");
+const Property = @import("../Property.zig").Property;
+const PropertyData = @import("../Property.zig").Data;
+const defaultCommonProperties = @import("../Property.zig").defaultCommonProperties;
+const basic_models = @import("../basic_models.zig");
+const line = @import("line.zig");
+const ellipse = @import("ellipse.zig");
+const broken = @import("broken.zig");
+const arc = @import("arc.zig");
 
 pub const Rect = basic_models.Rect;
 
@@ -54,8 +54,7 @@ fn requiredTagsFor(kind: Object.ShapeKind) []const std.meta.Tag(PropertyData) {
 }
 
 /// Локальные границы объекта (AABB в своих координатах).
-pub fn getLocalBounds(obj: *const Object) ?Rect {
-    ensure(obj, obj.shape) catch return null;
+pub fn getLocalBounds(obj: *const Object) !Rect {
     return switch (obj.shape) {
         .line => line.getLocalBounds(obj),
         .ellipse => ellipse.getLocalBounds(obj),
@@ -72,28 +71,25 @@ test "getLocalBounds" {
 
     var line_obj = try shape.createObject(allocator, .line);
     defer line_obj.deinit(allocator);
-    const line_bounds = getLocalBounds(&line_obj);
-    try std.testing.expect(line_bounds != null);
-    try std.testing.expect(line_bounds.?.x == 0);
-    try std.testing.expect(line_bounds.?.y == 0);
-    try std.testing.expect(line_bounds.?.w == 100);
-    try std.testing.expect(line_bounds.?.h == 0);
+    const line_bounds = try getLocalBounds(&line_obj);
+    try std.testing.expect(line_bounds.x == 0);
+    try std.testing.expect(line_bounds.y == 0);
+    try std.testing.expect(line_bounds.w == 100);
+    try std.testing.expect(line_bounds.h == 0);
 
     var ellipse_obj = try shape.createObject(allocator, .ellipse);
     defer ellipse_obj.deinit(allocator);
-    const ellipse_bounds = getLocalBounds(&ellipse_obj);
-    try std.testing.expect(ellipse_bounds != null);
-    try std.testing.expect(ellipse_bounds.?.x == -50);
-    try std.testing.expect(ellipse_bounds.?.y == -50);
-    try std.testing.expect(ellipse_bounds.?.w == 100);
-    try std.testing.expect(ellipse_bounds.?.h == 100);
+    const ellipse_bounds = try getLocalBounds(&ellipse_obj);
+    try std.testing.expect(ellipse_bounds.x == -50);
+    try std.testing.expect(ellipse_bounds.y == -50);
+    try std.testing.expect(ellipse_bounds.w == 100);
+    try std.testing.expect(ellipse_bounds.h == 100);
 
     var broken_obj = try shape.createObject(allocator, .broken);
     defer broken_obj.deinit(allocator);
-    const broken_bounds = getLocalBounds(&broken_obj);
-    try std.testing.expect(broken_bounds != null);
-    try std.testing.expect(broken_bounds.?.x == 0);
-    try std.testing.expect(broken_bounds.?.y == 0);
-    try std.testing.expect(broken_bounds.?.w == 80);
-    try std.testing.expect(broken_bounds.?.h == 60);
+    const broken_bounds = try getLocalBounds(&broken_obj);
+    try std.testing.expect(broken_bounds.x == 0);
+    try std.testing.expect(broken_bounds.y == 0);
+    try std.testing.expect(broken_bounds.w == 80);
+    try std.testing.expect(broken_bounds.h == 60);
 }
diff --git a/src/tests.zig b/src/tests.zig
index 65a82bd..99ceb59 100644
--- a/src/tests.zig
+++ b/src/tests.zig
@@ -4,7 +4,7 @@
 test "discover tests" {
     _ = @import("main.zig");
     _ = @import("models/Property.zig");
-    _ = @import("models/shape.zig");
+    _ = @import("models/shape/shape.zig");
 }
 
 // Убедиться, что выполнились все ожидаемые тесты: этот тест пройдёт только если до него дошли (т.е. все предыдущие прошли).