diff --git a/rsconcept/backend/apps/library/tests/s_views/t_library.py b/rsconcept/backend/apps/library/tests/s_views/t_library.py
index ac1cd0be..a61a272d 100644
--- a/rsconcept/backend/apps/library/tests/s_views/t_library.py
+++ b/rsconcept/backend/apps/library/tests/s_views/t_library.py
@@ -68,8 +68,6 @@ class TestLibraryViewset(EndpointTester):
         self.assertEqual(response.data['access_policy'], data['access_policy'])
         self.assertEqual(response.data['visible'], data['visible'])
         self.assertEqual(response.data['read_only'], data['read_only'])
-        self.assertEqual(oss.layout().data['operations'], [])
-        self.assertEqual(oss.layout().data['blocks'], [])
 
         self.logout()
         data = {'title': 'Title2'}
diff --git a/rsconcept/backend/apps/library/views/library.py b/rsconcept/backend/apps/library/views/library.py
index 95d36064..99ffe1d2 100644
--- a/rsconcept/backend/apps/library/views/library.py
+++ b/rsconcept/backend/apps/library/views/library.py
@@ -41,7 +41,7 @@ class LibraryViewSet(viewsets.ModelViewSet):
         else:
             serializer.save()
         if serializer.data.get('item_type') == m.LibraryItemType.OPERATION_SCHEMA:
-            Layout.objects.create(oss=serializer.instance, data={'operations': [], 'blocks': []})
+            Layout.objects.create(oss=serializer.instance, data=[])
 
     def perform_update(self, serializer) -> None:
         instance = serializer.save()
diff --git a/rsconcept/backend/apps/oss/migrations/0012 restructure_layout.py b/rsconcept/backend/apps/oss/migrations/0012 restructure_layout.py
new file mode 100644
index 00000000..3fcb9628
--- /dev/null
+++ b/rsconcept/backend/apps/oss/migrations/0012 restructure_layout.py	
@@ -0,0 +1,41 @@
+from django.db import migrations
+
+
+def migrate_layout(apps, schema_editor):
+    Layout = apps.get_model('oss', 'Layout')
+
+    for layout in Layout.objects.all():
+        previous_data = layout.data
+        new_layout = []
+
+        for operation in previous_data['operations']:
+            new_layout.append({
+                'nodeID': 'o' + str(operation['id']),
+                'x': operation['x'],
+                'y': operation['y'],
+                'width': 150,
+                'height': 40
+            })
+
+        for block in previous_data['blocks']:
+            new_layout.append({
+                'nodeID': 'b' + str(block['id']),
+                'x': block['x'],
+                'y': block['y'],
+                'width': block['width'],
+                'height': block['height']
+            })
+
+        layout.data = new_layout
+        layout.save(update_fields=['data'])
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('oss', '0011_remove_operation_position_x_and_more'),
+    ]
+
+    operations = [
+        migrations.RunPython(migrate_layout),
+    ]
diff --git a/rsconcept/backend/apps/oss/migrations/0013_alter_layout_data.py b/rsconcept/backend/apps/oss/migrations/0013_alter_layout_data.py
new file mode 100644
index 00000000..2540749f
--- /dev/null
+++ b/rsconcept/backend/apps/oss/migrations/0013_alter_layout_data.py
@@ -0,0 +1,18 @@
+# Generated by Django 5.2.1 on 2025-06-11 10:22
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('oss', '0012 restructure_layout'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='layout',
+            name='data',
+            field=models.JSONField(default=list, verbose_name='Расположение'),
+        ),
+    ]
diff --git a/rsconcept/backend/apps/oss/models/Layout.py b/rsconcept/backend/apps/oss/models/Layout.py
index 1f6efdd1..fabd765a 100644
--- a/rsconcept/backend/apps/oss/models/Layout.py
+++ b/rsconcept/backend/apps/oss/models/Layout.py
@@ -13,7 +13,7 @@ class Layout(Model):
 
     data = JSONField(
         verbose_name='Расположение',
-        default=dict
+        default=list
     )
 
     class Meta:
diff --git a/rsconcept/backend/apps/oss/models/OperationSchema.py b/rsconcept/backend/apps/oss/models/OperationSchema.py
index 79b1a7fc..8cd3b039 100644
--- a/rsconcept/backend/apps/oss/models/OperationSchema.py
+++ b/rsconcept/backend/apps/oss/models/OperationSchema.py
@@ -40,7 +40,7 @@ class OperationSchema:
     def create(**kwargs) -> 'OperationSchema':
         ''' Create LibraryItem via OperationSchema. '''
         model = LibraryItem.objects.create(item_type=LibraryItemType.OPERATION_SCHEMA, **kwargs)
-        Layout.objects.create(oss=model, data={'operations': [], 'blocks': []})
+        Layout.objects.create(oss=model, data=[])
         return OperationSchema(model)
 
     @staticmethod
diff --git a/rsconcept/backend/apps/oss/serializers/basics.py b/rsconcept/backend/apps/oss/serializers/basics.py
index 11caab87..ec568260 100644
--- a/rsconcept/backend/apps/oss/serializers/basics.py
+++ b/rsconcept/backend/apps/oss/serializers/basics.py
@@ -2,16 +2,9 @@
 from rest_framework import serializers
 
 
-class OperationNodeSerializer(serializers.Serializer):
-    ''' Operation position. '''
-    id = serializers.IntegerField()
-    x = serializers.FloatField()
-    y = serializers.FloatField()
-
-
-class BlockNodeSerializer(serializers.Serializer):
+class NodeSerializer(serializers.Serializer):
     ''' Block position. '''
-    id = serializers.IntegerField()
+    nodeID = serializers.CharField()
     x = serializers.FloatField()
     y = serializers.FloatField()
     width = serializers.FloatField()
@@ -19,13 +12,8 @@ class BlockNodeSerializer(serializers.Serializer):
 
 
 class LayoutSerializer(serializers.Serializer):
-    ''' Layout for OperationSchema. '''
-    blocks = serializers.ListField(
-        child=BlockNodeSerializer()
-    )
-    operations = serializers.ListField(
-        child=OperationNodeSerializer()
-    )
+    ''' Serializer: Layout data. '''
+    data = serializers.ListField(child=NodeSerializer())  # type: ignore
 
 
 class SubstitutionExSerializer(serializers.Serializer):
diff --git a/rsconcept/backend/apps/oss/serializers/data_access.py b/rsconcept/backend/apps/oss/serializers/data_access.py
index 98329c7c..9591ee05 100644
--- a/rsconcept/backend/apps/oss/serializers/data_access.py
+++ b/rsconcept/backend/apps/oss/serializers/data_access.py
@@ -13,7 +13,7 @@ from apps.rsform.serializers import SubstitutionSerializerBase
 from shared import messages as msg
 
 from ..models import Argument, Block, Inheritance, Operation, OperationSchema, OperationType
-from .basics import LayoutSerializer, SubstitutionExSerializer
+from .basics import NodeSerializer, SubstitutionExSerializer
 
 
 class OperationSerializer(serializers.ModelSerializer):
@@ -52,7 +52,9 @@ class CreateBlockSerializer(serializers.Serializer):
             model = Block
             fields = 'title', 'description', 'parent'
 
-    layout = LayoutSerializer()
+    layout = serializers.ListField(
+        child=NodeSerializer()
+    )
     item_data = BlockCreateData()
     width = serializers.FloatField()
     height = serializers.FloatField()
@@ -100,7 +102,10 @@ class UpdateBlockSerializer(serializers.Serializer):
             model = Block
             fields = 'title', 'description', 'parent'
 
-    layout = LayoutSerializer(required=False)
+    layout = serializers.ListField(
+        child=NodeSerializer(),
+        required=False
+    )
     target = PKField(many=False, queryset=Block.objects.all())
     item_data = UpdateBlockData()
 
@@ -127,7 +132,9 @@ class UpdateBlockSerializer(serializers.Serializer):
 
 class DeleteBlockSerializer(serializers.Serializer):
     ''' Serializer: Delete block. '''
-    layout = LayoutSerializer()
+    layout = serializers.ListField(
+        child=NodeSerializer()
+    )
     target = PKField(many=False, queryset=Block.objects.all().only('oss_id'))
 
     def validate(self, attrs):
@@ -142,7 +149,9 @@ class DeleteBlockSerializer(serializers.Serializer):
 
 class MoveItemsSerializer(serializers.Serializer):
     ''' Serializer: Move items to another parent. '''
-    layout = LayoutSerializer()
+    layout = serializers.ListField(
+        child=NodeSerializer()
+    )
     operations = PKField(many=True, queryset=Operation.objects.all().only('oss_id', 'parent'))
     blocks = PKField(many=True, queryset=Block.objects.all().only('oss_id', 'parent'))
     destination = PKField(many=False, queryset=Block.objects.all().only('oss_id'), allow_null=True)
@@ -196,8 +205,12 @@ class CreateOperationSerializer(serializers.Serializer):
                 'alias', 'operation_type', 'title', \
                 'description', 'result', 'parent'
 
-    layout = LayoutSerializer()
+    layout = serializers.ListField(
+        child=NodeSerializer()
+    )
     item_data = CreateOperationData()
+    width = serializers.FloatField()
+    height = serializers.FloatField()
     position_x = serializers.FloatField()
     position_y = serializers.FloatField()
     create_schema = serializers.BooleanField(default=False, required=False)
@@ -230,7 +243,10 @@ class UpdateOperationSerializer(serializers.Serializer):
             model = Operation
             fields = 'alias', 'title', 'description', 'parent'
 
-    layout = LayoutSerializer(required=False)
+    layout = serializers.ListField(
+        child=NodeSerializer(),
+        required=False
+    )
     target = PKField(many=False, queryset=Operation.objects.all())
     item_data = UpdateOperationData()
     arguments = PKField(many=True, queryset=Operation.objects.all().only('oss_id', 'result_id'), required=False)
@@ -297,7 +313,9 @@ class UpdateOperationSerializer(serializers.Serializer):
 
 class DeleteOperationSerializer(serializers.Serializer):
     ''' Serializer: Delete operation. '''
-    layout = LayoutSerializer()
+    layout = serializers.ListField(
+        child=NodeSerializer()
+    )
     target = PKField(many=False, queryset=Operation.objects.all().only('oss_id', 'result'))
     keep_constituents = serializers.BooleanField(default=False, required=False)
     delete_schema = serializers.BooleanField(default=False, required=False)
@@ -314,7 +332,9 @@ class DeleteOperationSerializer(serializers.Serializer):
 
 class TargetOperationSerializer(serializers.Serializer):
     ''' Serializer: Target single operation. '''
-    layout = LayoutSerializer()
+    layout = serializers.ListField(
+        child=NodeSerializer()
+    )
     target = PKField(many=False, queryset=Operation.objects.all().only('oss_id', 'result_id'))
 
     def validate(self, attrs):
@@ -329,7 +349,9 @@ class TargetOperationSerializer(serializers.Serializer):
 
 class SetOperationInputSerializer(serializers.Serializer):
     ''' Serializer: Set input schema for operation. '''
-    layout = LayoutSerializer()
+    layout = serializers.ListField(
+        child=NodeSerializer()
+    )
     target = PKField(many=False, queryset=Operation.objects.all())
     input = PKField(
         many=False,
@@ -366,7 +388,9 @@ class OperationSchemaSerializer(serializers.ModelSerializer):
     substitutions = serializers.ListField(
         child=SubstitutionExSerializer()
     )
-    layout = LayoutSerializer()
+    layout = serializers.ListField(
+        child=NodeSerializer()
+    )
 
     class Meta:
         ''' serializer metadata. '''
@@ -459,7 +483,7 @@ class RelocateConstituentsSerializer(serializers.Serializer):
 
         return attrs
 
-# ====== Internals =================================================================================
+# ====== Internals ============
 
 
 def _collect_descendants(start_blocks: list[Block]) -> set[int]:
diff --git a/rsconcept/backend/apps/oss/tests/s_propagation/t_attributes.py b/rsconcept/backend/apps/oss/tests/s_propagation/t_attributes.py
index 371f115e..df3f8525 100644
--- a/rsconcept/backend/apps/oss/tests/s_propagation/t_attributes.py
+++ b/rsconcept/backend/apps/oss/tests/s_propagation/t_attributes.py
@@ -59,14 +59,11 @@ class TestChangeAttributes(EndpointTester):
         self.operation3.refresh_from_db()
         self.ks3 = RSForm(self.operation3.result)
 
-        self.layout_data = {
-            'operations': [
-                {'id': self.operation1.pk, 'x': 0, 'y': 0},
-                {'id': self.operation2.pk, 'x': 0, 'y': 0},
-                {'id': self.operation3.pk, 'x': 0, 'y': 0},
-            ],
-            'blocks': []
-        }
+        self.layout_data = [
+            {'nodeID': 'o' + str(self.operation1.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+            {'nodeID': 'o' + str(self.operation2.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+            {'nodeID': 'o' + str(self.operation3.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+        ]
         layout = self.owned.layout()
         layout.data = self.layout_data
         layout.save()
diff --git a/rsconcept/backend/apps/oss/tests/s_propagation/t_constituents.py b/rsconcept/backend/apps/oss/tests/s_propagation/t_constituents.py
index b27283a6..84ee598c 100644
--- a/rsconcept/backend/apps/oss/tests/s_propagation/t_constituents.py
+++ b/rsconcept/backend/apps/oss/tests/s_propagation/t_constituents.py
@@ -57,14 +57,11 @@ class TestChangeConstituents(EndpointTester):
         self.ks3 = RSForm(self.operation3.result)
         self.assertEqual(self.ks3.constituents().count(), 4)
 
-        self.layout_data = {
-            'operations': [
-                {'id': self.operation1.pk, 'x': 0, 'y': 0},
-                {'id': self.operation2.pk, 'x': 0, 'y': 0},
-                {'id': self.operation3.pk, 'x': 0, 'y': 0},
-            ],
-            'blocks': []
-        }
+        self.layout_data = [
+            {'nodeID': 'o' + str(self.operation1.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+            {'nodeID': 'o' + str(self.operation2.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+            {'nodeID': 'o' + str(self.operation3.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+        ]
         layout = self.owned.layout()
         layout.data = self.layout_data
         layout.save()
diff --git a/rsconcept/backend/apps/oss/tests/s_propagation/t_operations.py b/rsconcept/backend/apps/oss/tests/s_propagation/t_operations.py
index eddad306..863fe423 100644
--- a/rsconcept/backend/apps/oss/tests/s_propagation/t_operations.py
+++ b/rsconcept/backend/apps/oss/tests/s_propagation/t_operations.py
@@ -107,16 +107,13 @@ class TestChangeOperations(EndpointTester):
             convention='KS5D4'
         )
 
-        self.layout_data = {
-            'operations': [
-                {'id': self.operation1.pk, 'x': 0, 'y': 0},
-                {'id': self.operation2.pk, 'x': 0, 'y': 0},
-                {'id': self.operation3.pk, 'x': 0, 'y': 0},
-                {'id': self.operation4.pk, 'x': 0, 'y': 0},
-                {'id': self.operation5.pk, 'x': 0, 'y': 0},
-            ],
-            'blocks': []
-        }
+        self.layout_data = [
+            {'nodeID': 'o' + str(self.operation1.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+            {'nodeID': 'o' + str(self.operation2.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+            {'nodeID': 'o' + str(self.operation3.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+            {'nodeID': 'o' + str(self.operation4.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+            {'nodeID': 'o' + str(self.operation5.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40}
+        ]
         layout = self.owned.layout()
         layout.data = self.layout_data
         layout.save()
diff --git a/rsconcept/backend/apps/oss/tests/s_propagation/t_substitutions.py b/rsconcept/backend/apps/oss/tests/s_propagation/t_substitutions.py
index c99bfb29..ce2f22c8 100644
--- a/rsconcept/backend/apps/oss/tests/s_propagation/t_substitutions.py
+++ b/rsconcept/backend/apps/oss/tests/s_propagation/t_substitutions.py
@@ -107,16 +107,13 @@ class TestChangeSubstitutions(EndpointTester):
             convention='KS5D4'
         )
 
-        self.layout_data = {
-            'operations': [
-                {'id': self.operation1.pk, 'x': 0, 'y': 0},
-                {'id': self.operation2.pk, 'x': 0, 'y': 0},
-                {'id': self.operation3.pk, 'x': 0, 'y': 0},
-                {'id': self.operation4.pk, 'x': 0, 'y': 0},
-                {'id': self.operation5.pk, 'x': 0, 'y': 0},
-            ],
-            'blocks': []
-        }
+        self.layout_data = [
+            {'nodeID': 'o' + str(self.operation1.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+            {'nodeID': 'o' + str(self.operation2.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+            {'nodeID': 'o' + str(self.operation3.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+            {'nodeID': 'o' + str(self.operation4.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+            {'nodeID': 'o' + str(self.operation5.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+        ]
         layout = self.owned.layout()
         layout.data = self.layout_data
         layout.save()
diff --git a/rsconcept/backend/apps/oss/tests/s_views/t_blocks.py b/rsconcept/backend/apps/oss/tests/s_views/t_blocks.py
index 3bc190c6..ac1c608a 100644
--- a/rsconcept/backend/apps/oss/tests/s_views/t_blocks.py
+++ b/rsconcept/backend/apps/oss/tests/s_views/t_blocks.py
@@ -49,16 +49,14 @@ class TestOssBlocks(EndpointTester):
             title='3',
             parent=self.block1
         )
-        self.layout_data = {
-            'operations': [
-                {'id': self.operation1.pk, 'x': 0, 'y': 0},
-                {'id': self.operation2.pk, 'x': 0, 'y': 0},
-            ],
-            'blocks': [
-                {'id': self.block1.pk, 'x': 0, 'y': 0, 'width': 0.5, 'height': 0.5},
-                {'id': self.block2.pk, 'x': 0, 'y': 0, 'width': 0.5, 'height': 0.5},
-            ]
-        }
+        self.layout_data = [
+            {'nodeID': 'o' + str(self.operation1.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+            {'nodeID': 'o' + str(self.operation2.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+
+            {'nodeID': 'b' + str(self.block1.pk), 'x': 0, 'y': 0, 'width': 0.5, 'height': 0.5},
+            {'nodeID': 'b' + str(self.block2.pk), 'x': 0, 'y': 0, 'width': 0.5, 'height': 0.5},
+        ]
+
         layout = self.owned.layout()
         layout.data = self.layout_data
         layout.save()
@@ -88,7 +86,7 @@ class TestOssBlocks(EndpointTester):
         self.assertEqual(len(response.data['oss']['blocks']), 3)
         new_block = response.data['new_block']
         layout = response.data['oss']['layout']
-        item = [item for item in layout['blocks'] if item['id'] == new_block['id']][0]
+        item = [item for item in layout if item['nodeID'] == 'b' + str(new_block['id'])][0]
         self.assertEqual(new_block['title'], data['item_data']['title'])
         self.assertEqual(new_block['description'], data['item_data']['description'])
         self.assertEqual(new_block['parent'], None)
diff --git a/rsconcept/backend/apps/oss/tests/s_views/t_operations.py b/rsconcept/backend/apps/oss/tests/s_views/t_operations.py
index 249f47bd..b1833f31 100644
--- a/rsconcept/backend/apps/oss/tests/s_views/t_operations.py
+++ b/rsconcept/backend/apps/oss/tests/s_views/t_operations.py
@@ -54,14 +54,11 @@ class TestOssOperations(EndpointTester):
             alias='3',
             operation_type=OperationType.SYNTHESIS
         )
-        self.layout_data = {
-            'operations': [
-                {'id': self.operation1.pk, 'x': 0, 'y': 0},
-                {'id': self.operation2.pk, 'x': 0, 'y': 0},
-                {'id': self.operation3.pk, 'x': 0, 'y': 0},
-            ],
-            'blocks': []
-        }
+        self.layout_data = [
+            {'nodeID': 'o' + str(self.operation1.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+            {'nodeID': 'o' + str(self.operation2.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+            {'nodeID': 'o' + str(self.operation3.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+        ]
         layout = self.owned.layout()
         layout.data = self.layout_data
         layout.save()
@@ -87,7 +84,9 @@ class TestOssOperations(EndpointTester):
             },
             'layout': self.layout_data,
             'position_x': 1,
-            'position_y': 1
+            'position_y': 1,
+            'width': 500,
+            'height': 50
 
         }
         self.executeBadData(data=data)
@@ -102,7 +101,7 @@ class TestOssOperations(EndpointTester):
         self.assertEqual(len(response.data['oss']['operations']), 4)
         new_operation = response.data['new_operation']
         layout = response.data['oss']['layout']
-        item = [item for item in layout['operations'] if item['id'] == new_operation['id']][0]
+        item = [item for item in layout if item['nodeID'] == 'o' + str(new_operation['id'])][0]
         self.assertEqual(new_operation['alias'], data['item_data']['alias'])
         self.assertEqual(new_operation['operation_type'], data['item_data']['operation_type'])
         self.assertEqual(new_operation['title'], data['item_data']['title'])
@@ -111,6 +110,8 @@ class TestOssOperations(EndpointTester):
         self.assertEqual(new_operation['parent'], None)
         self.assertEqual(item['x'], data['position_x'])
         self.assertEqual(item['y'], data['position_y'])
+        self.assertEqual(item['width'], data['width'])
+        self.assertEqual(item['height'], data['height'])
         self.operation1.refresh_from_db()
 
         self.executeForbidden(data=data, item=self.unowned_id)
@@ -132,7 +133,9 @@ class TestOssOperations(EndpointTester):
             },
             'layout': self.layout_data,
             'position_x': 1,
-            'position_y': 1
+            'position_y': 1,
+            'width': 500,
+            'height': 50
 
         }
         self.executeBadData(data=data, item=self.owned_id)
@@ -160,6 +163,8 @@ class TestOssOperations(EndpointTester):
             'layout': self.layout_data,
             'position_x': 1,
             'position_y': 1,
+            'width': 500,
+            'height': 50,
             'arguments': [self.operation1.pk, self.operation3.pk]
         }
         response = self.executeCreated(data=data, item=self.owned_id)
@@ -185,7 +190,9 @@ class TestOssOperations(EndpointTester):
             },
             'layout': self.layout_data,
             'position_x': 1,
-            'position_y': 1
+            'position_y': 1,
+            'width': 500,
+            'height': 50
         }
         response = self.executeCreated(data=data, item=self.owned_id)
         new_operation = response.data['new_operation']
@@ -207,7 +214,9 @@ class TestOssOperations(EndpointTester):
             'create_schema': True,
             'layout': self.layout_data,
             'position_x': 1,
-            'position_y': 1
+            'position_y': 1,
+            'width': 500,
+            'height': 50
         }
         self.executeBadData(data=data, item=self.owned_id)
         data['item_data']['result'] = None
@@ -244,7 +253,7 @@ class TestOssOperations(EndpointTester):
         self.login()
         response = self.executeOK(data=data)
         layout = response.data['layout']
-        deleted_items = [item for item in layout['operations'] if item['id'] == data['target']]
+        deleted_items = [item for item in layout if item['nodeID'] == 'o' + str(data['target'])]
         self.assertEqual(len(response.data['operations']), 2)
         self.assertEqual(len(deleted_items), 0)
 
diff --git a/rsconcept/backend/apps/oss/tests/s_views/t_oss.py b/rsconcept/backend/apps/oss/tests/s_views/t_oss.py
index 8e55f271..969b23ff 100644
--- a/rsconcept/backend/apps/oss/tests/s_views/t_oss.py
+++ b/rsconcept/backend/apps/oss/tests/s_views/t_oss.py
@@ -55,11 +55,11 @@ class TestOssViewset(EndpointTester):
             alias='3',
             operation_type=OperationType.SYNTHESIS
         )
-        self.layout_data = {'operations': [
-            {'id': self.operation1.pk, 'x': 0, 'y': 0},
-            {'id': self.operation2.pk, 'x': 0, 'y': 0},
-            {'id': self.operation3.pk, 'x': 0, 'y': 0},
-        ], 'blocks': []}
+        self.layout_data = [
+            {'nodeID': 'o' + str(self.operation1.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+            {'nodeID': 'o' + str(self.operation2.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40},
+            {'nodeID': 'o' + str(self.operation3.pk), 'x': 0, 'y': 0, 'width': 150, 'height': 40}
+        ]
         layout = self.owned.layout()
         layout.data = self.layout_data
         layout.save()
@@ -107,10 +107,9 @@ class TestOssViewset(EndpointTester):
         self.assertEqual(arguments[1]['argument'], self.operation2.pk)
 
         layout = response.data['layout']
-        self.assertEqual(layout['blocks'], [])
-        self.assertEqual(layout['operations'][0], {'id': self.operation1.pk, 'x': 0, 'y': 0})
-        self.assertEqual(layout['operations'][1], {'id': self.operation2.pk, 'x': 0, 'y': 0})
-        self.assertEqual(layout['operations'][2], {'id': self.operation3.pk, 'x': 0, 'y': 0})
+        self.assertEqual(layout[0], self.layout_data[0])
+        self.assertEqual(layout[1], self.layout_data[1])
+        self.assertEqual(layout[2], self.layout_data[2])
 
         self.executeOK(item=self.unowned_id)
         self.executeForbidden(item=self.private_id)
@@ -126,23 +125,21 @@ class TestOssViewset(EndpointTester):
         self.populateData()
         self.executeBadData(item=self.owned_id)
 
-        data = {'operations': [], 'blocks': []}
+        data = {'data': []}
         self.executeOK(data=data)
 
-        data = {
-            'operations': [
-                {'id': self.operation1.pk, 'x': 42.1, 'y': 1337},
-                {'id': self.operation2.pk, 'x': 36.1, 'y': 1437},
-                {'id': self.operation3.pk, 'x': 36.1, 'y': 1435}
-            ], 'blocks': []
-        }
+        data = {'data': [
+            {'nodeID': 'o' + str(self.operation1.pk), 'x': 42.1, 'y': 1337, 'width': 150, 'height': 40},
+            {'nodeID': 'o' + str(self.operation2.pk), 'x': 36.1, 'y': 1437, 'width': 150, 'height': 40},
+            {'nodeID': 'o' + str(self.operation3.pk), 'x': 36.1, 'y': 1435, 'width': 150, 'height': 40}
+        ]}
         self.toggle_admin(True)
         self.executeOK(data=data, item=self.unowned_id)
 
         self.toggle_admin(False)
         self.executeOK(data=data, item=self.owned_id)
         self.owned.refresh_from_db()
-        self.assertEqual(self.owned.layout().data, data)
+        self.assertEqual(self.owned.layout().data, data['data'])
 
         self.executeForbidden(data=data, item=self.unowned_id)
         self.executeForbidden(data=data, item=self.private_id)
diff --git a/rsconcept/backend/apps/oss/views/oss.py b/rsconcept/backend/apps/oss/views/oss.py
index e99d2746..07cb7071 100644
--- a/rsconcept/backend/apps/oss/views/oss.py
+++ b/rsconcept/backend/apps/oss/views/oss.py
@@ -91,7 +91,7 @@ class OssViewSet(viewsets.GenericViewSet, generics.ListAPIView, generics.Retriev
         ''' Endpoint: Update schema layout. '''
         serializer = s.LayoutSerializer(data=request.data)
         serializer.is_valid(raise_exception=True)
-        m.OperationSchema(self.get_object()).update_layout(serializer.validated_data)
+        m.OperationSchema(self.get_object()).update_layout(serializer.validated_data['data'])
         return Response(status=c.HTTP_200_OK)
 
     @extend_schema(
@@ -120,8 +120,8 @@ class OssViewSet(viewsets.GenericViewSet, generics.ListAPIView, generics.Retriev
         children_operations: list[m.Operation] = serializer.validated_data['children_operations']
         with transaction.atomic():
             new_block = oss.create_block(**serializer.validated_data['item_data'])
-            layout['blocks'].append({
-                'id': new_block.pk,
+            layout.append({
+                'nodeID': 'b' + str(new_block.pk),
                 'x': serializer.validated_data['position_x'],
                 'y': serializer.validated_data['position_y'],
                 'width': serializer.validated_data['width'],
@@ -205,7 +205,7 @@ class OssViewSet(viewsets.GenericViewSet, generics.ListAPIView, generics.Retriev
         oss = m.OperationSchema(self.get_object())
         block = cast(m.Block, serializer.validated_data['target'])
         layout = serializer.validated_data['layout']
-        layout['blocks'] = [x for x in layout['blocks'] if x['id'] != block.pk]
+        layout = [x for x in layout if x['nodeID'] != 'b' + str(block.pk)]
         with transaction.atomic():
             oss.delete_block(block)
             oss.update_layout(layout)
@@ -274,10 +274,12 @@ class OssViewSet(viewsets.GenericViewSet, generics.ListAPIView, generics.Retriev
         layout = serializer.validated_data['layout']
         with transaction.atomic():
             new_operation = oss.create_operation(**serializer.validated_data['item_data'])
-            layout['operations'].append({
-                'id': new_operation.pk,
+            layout.append({
+                'nodeID': 'o' + str(new_operation.pk),
                 'x': serializer.validated_data['position_x'],
-                'y': serializer.validated_data['position_y']
+                'y': serializer.validated_data['position_y'],
+                'width': serializer.validated_data['width'],
+                'height': serializer.validated_data['height']
             })
             oss.update_layout(layout)
 
@@ -384,7 +386,7 @@ class OssViewSet(viewsets.GenericViewSet, generics.ListAPIView, generics.Retriev
         operation = cast(m.Operation, serializer.validated_data['target'])
         old_schema = operation.result
         layout = serializer.validated_data['layout']
-        layout['operations'] = [x for x in layout['operations'] if x['id'] != operation.pk]
+        layout = [x for x in layout if x['nodeID'] != 'o' + str(operation.pk)]
         with transaction.atomic():
             oss.delete_operation(operation.pk, serializer.validated_data['keep_constituents'])
             oss.update_layout(layout)
diff --git a/rsconcept/frontend/src/features/oss/backend/api.ts b/rsconcept/frontend/src/features/oss/backend/api.ts
index dcf08b8b..c27eede9 100644
--- a/rsconcept/frontend/src/features/oss/backend/api.ts
+++ b/rsconcept/frontend/src/features/oss/backend/api.ts
@@ -50,7 +50,7 @@ export const ossApi = {
     axiosPatch({
       endpoint: `/api/oss/${itemID}/update-layout`,
       request: {
-        data: data,
+        data: { data: data },
         successMessage: isSilent ? undefined : infoMsg.changesSaved
       }
     }),
diff --git a/rsconcept/frontend/src/features/oss/backend/oss-loader.ts b/rsconcept/frontend/src/features/oss/backend/oss-loader.ts
index 3260c1a9..d9f14b4a 100644
--- a/rsconcept/frontend/src/features/oss/backend/oss-loader.ts
+++ b/rsconcept/frontend/src/features/oss/backend/oss-loader.ts
@@ -90,7 +90,7 @@ export class OssLoader {
     this.graph.topologicalOrder().forEach(operationID => {
       const operation = this.operationByID.get(operationID)!;
       const schema = this.items.find(item => item.id === operation.result);
-      const position = this.oss.layout.operations.find(item => item.id === operationID);
+      const position = this.oss.layout.find(item => item.nodeID === operation.nodeID);
       operation.x = position?.x ?? 0;
       operation.y = position?.y ?? 0;
       operation.is_consolidation = this.inferConsolidation(operationID);
@@ -104,7 +104,7 @@ export class OssLoader {
 
   private inferBlockAttributes() {
     this.oss.blocks.forEach(block => {
-      const geometry = this.oss.layout.blocks.find(item => item.id === block.id);
+      const geometry = this.oss.layout.find(item => item.nodeID === block.nodeID);
       block.x = geometry?.x ?? 0;
       block.y = geometry?.y ?? 0;
       block.width = geometry?.width ?? BLOCK_NODE_MIN_WIDTH;
diff --git a/rsconcept/frontend/src/features/oss/backend/types.ts b/rsconcept/frontend/src/features/oss/backend/types.ts
index 84e78a49..09ed7a9e 100644
--- a/rsconcept/frontend/src/features/oss/backend/types.ts
+++ b/rsconcept/frontend/src/features/oss/backend/types.ts
@@ -72,11 +72,8 @@ export type IRelocateConstituentsDTO = z.infer<typeof schemaRelocateConstituents
 /** Represents {@link IConstituenta} reference. */
 export type IConstituentaReference = z.infer<typeof schemaConstituentaReference>;
 
-/** Represents {@link IOperation} position. */
-export type IOperationPosition = z.infer<typeof schemaOperationPosition>;
-
-/** Represents {@link IBlock} position. */
-export type IBlockPosition = z.infer<typeof schemaBlockPosition>;
+/** Represents {@link IOperationSchema} node position. */
+export type INodePosition = z.infer<typeof schemaNodePosition>;
 
 // ====== Schemas ======
 export const schemaOperationType = z.enum(Object.values(OperationType) as [OperationType, ...OperationType[]]);
@@ -108,24 +105,15 @@ export const schemaCstSubstituteInfo = schemaSubstituteConstituents.extend({
   substitution_term: z.string()
 });
 
-export const schemaOperationPosition = z.strictObject({
-  id: z.number(),
-  x: z.number(),
-  y: z.number()
-});
-
-export const schemaBlockPosition = z.strictObject({
-  id: z.number(),
+export const schemaNodePosition = z.strictObject({
+  nodeID: z.string(),
   x: z.number(),
   y: z.number(),
   width: z.number(),
   height: z.number()
 });
 
-export const schemaOssLayout = z.strictObject({
-  operations: z.array(schemaOperationPosition),
-  blocks: z.array(schemaBlockPosition)
-});
+export const schemaOssLayout = z.array(schemaNodePosition);
 
 export const schemaOperationSchema = schemaLibraryItem.extend({
   editors: z.number().array(),
@@ -188,6 +176,8 @@ export const schemaCreateOperation = z.strictObject({
   }),
   position_x: z.number(),
   position_y: z.number(),
+  width: z.number(),
+  height: z.number(),
   arguments: z.array(z.number()),
   create_schema: z.boolean()
 });
diff --git a/rsconcept/frontend/src/features/oss/dialogs/dlg-create-operation/dlg-create-operation.tsx b/rsconcept/frontend/src/features/oss/dialogs/dlg-create-operation/dlg-create-operation.tsx
index 561f8d6e..6cf89754 100644
--- a/rsconcept/frontend/src/features/oss/dialogs/dlg-create-operation/dlg-create-operation.tsx
+++ b/rsconcept/frontend/src/features/oss/dialogs/dlg-create-operation/dlg-create-operation.tsx
@@ -13,7 +13,7 @@ import { useDialogsStore } from '@/stores/dialogs';
 import { type ICreateOperationDTO, OperationType, schemaCreateOperation } from '../../backend/types';
 import { useCreateOperation } from '../../backend/use-create-operation';
 import { describeOperationType, labelOperationType } from '../../labels';
-import { type LayoutManager } from '../../models/oss-layout-api';
+import { type LayoutManager, OPERATION_NODE_HEIGHT, OPERATION_NODE_WIDTH } from '../../models/oss-layout-api';
 
 import { TabInputOperation } from './tab-input-operation';
 import { TabSynthesisOperation } from './tab-synthesis-operation';
@@ -54,6 +54,8 @@ export function DlgCreateOperation() {
       position_x: defaultX,
       position_y: defaultY,
       arguments: initialInputs,
+      width: OPERATION_NODE_WIDTH,
+      height: OPERATION_NODE_HEIGHT,
       create_schema: false,
       layout: manager.layout
     },
diff --git a/rsconcept/frontend/src/features/oss/models/oss-layout-api.ts b/rsconcept/frontend/src/features/oss/models/oss-layout-api.ts
index 74b3cfdf..b560860b 100644
--- a/rsconcept/frontend/src/features/oss/models/oss-layout-api.ts
+++ b/rsconcept/frontend/src/features/oss/models/oss-layout-api.ts
@@ -1,10 +1,4 @@
-import {
-  type IBlockPosition,
-  type ICreateBlockDTO,
-  type ICreateOperationDTO,
-  type IOperationPosition,
-  type IOssLayout
-} from '../backend/types';
+import { type ICreateBlockDTO, type ICreateOperationDTO, type INodePosition, type IOssLayout } from '../backend/types';
 
 import { type IOperationSchema } from './oss';
 import { type Position2D, type Rectangle2D } from './oss-layout';
@@ -12,8 +6,8 @@ import { type Position2D, type Rectangle2D } from './oss-layout';
 export const GRID_SIZE = 10; // pixels - size of OSS grid
 const MIN_DISTANCE = 2 * GRID_SIZE; // pixels - minimum distance between nodes
 
-const OPERATION_NODE_WIDTH = 150;
-const OPERATION_NODE_HEIGHT = 40;
+export const OPERATION_NODE_WIDTH = 150;
+export const OPERATION_NODE_HEIGHT = 40;
 
 /** Layout manipulations for {@link IOperationSchema}. */
 export class LayoutManager {
@@ -30,27 +24,30 @@ export class LayoutManager {
   }
 
   /** Calculate insert position for a new {@link IOperation} */
-  newOperationPosition(data: ICreateOperationDTO): Position2D {
-    let result = { x: data.position_x, y: data.position_y };
-    const operations = this.layout.operations;
-    const parentNode = this.layout.blocks.find(pos => pos.id === data.item_data.parent);
-    if (operations.length === 0) {
+  newOperationPosition(data: ICreateOperationDTO): Rectangle2D {
+    let result = { x: data.position_x, y: data.position_y, width: data.width, height: data.height };
+    const parentNode = this.layout.find(pos => pos.nodeID === `b${data.item_data.parent}`);
+    if (this.oss.operations.length === 0) {
       return result;
     }
 
+    const operations = this.layout.filter(pos => pos.nodeID.startsWith('o'));
     if (data.arguments.length !== 0) {
-      result = calculatePositionFromArgs(data.arguments, operations);
+      const pos = calculatePositionFromArgs(
+        operations.filter(node => data.arguments.includes(Number(node.nodeID.slice(1))))
+      );
+      result.x = pos.x;
+      result.y = pos.y;
     } else if (parentNode) {
       result.x = parentNode.x + MIN_DISTANCE;
       result.y = parentNode.y + MIN_DISTANCE;
     } else {
-      result = this.calculatePositionForFreeOperation(result);
+      const pos = this.calculatePositionForFreeOperation(result);
+      result.x = pos.x;
+      result.y = pos.y;
     }
 
-    result = preventOverlap(
-      { ...result, width: OPERATION_NODE_WIDTH, height: OPERATION_NODE_HEIGHT },
-      operations.map(node => ({ ...node, width: OPERATION_NODE_WIDTH, height: OPERATION_NODE_HEIGHT }))
-    );
+    result = preventOverlap(result, operations);
 
     if (parentNode) {
       const borderX = result.x + OPERATION_NODE_WIDTH + MIN_DISTANCE;
@@ -64,18 +61,18 @@ export class LayoutManager {
       // TODO: trigger cascading updates
     }
 
-    return { x: result.x, y: result.y };
+    return result;
   }
 
   /** Calculate insert position for a new {@link IBlock} */
   newBlockPosition(data: ICreateBlockDTO): Rectangle2D {
     const block_nodes = data.children_blocks
-      .map(id => this.layout.blocks.find(block => block.id === id))
+      .map(id => this.layout.find(block => block.nodeID === `b${id}`))
       .filter(node => !!node);
     const operation_nodes = data.children_operations
-      .map(id => this.layout.operations.find(operation => operation.id === id))
+      .map(id => this.layout.find(operation => operation.nodeID === `o${id}`))
       .filter(node => !!node);
-    const parentNode = this.layout.blocks.find(pos => pos.id === data.item_data.parent);
+    const parentNode = this.layout.find(pos => pos.nodeID === `b${data.item_data.parent}`);
 
     let result: Rectangle2D = { x: data.position_x, y: data.position_y, width: data.width, height: data.height };
 
@@ -98,19 +95,21 @@ export class LayoutManager {
 
     if (block_nodes.length === 0 && operation_nodes.length === 0) {
       if (parentNode) {
-        const siblings = this.oss.blocks.filter(block => block.parent === parentNode.id).map(block => block.id);
+        const siblings = this.oss.blocks
+          .filter(block => block.parent === data.item_data.parent)
+          .map(block => block.nodeID);
         if (siblings.length > 0) {
           result = preventOverlap(
             result,
-            this.layout.blocks.filter(block => siblings.includes(block.id))
+            this.layout.filter(node => siblings.includes(node.nodeID))
           );
         }
       } else {
-        const rootBlocks = this.oss.blocks.filter(block => block.parent === null).map(block => block.id);
+        const rootBlocks = this.oss.blocks.filter(block => block.parent === null).map(block => block.nodeID);
         if (rootBlocks.length > 0) {
           result = preventOverlap(
             result,
-            this.layout.blocks.filter(block => rootBlocks.includes(block.id))
+            this.layout.filter(node => rootBlocks.includes(node.nodeID))
           );
         }
       }
@@ -133,7 +132,34 @@ export class LayoutManager {
 
   /** Update layout when parent changes */
   onOperationChangeParent(targetID: number, newParent: number | null) {
-    console.error('not implemented', targetID, newParent);
+    const targetNode = this.layout.find(pos => pos.nodeID === `o${targetID}`);
+    if (!targetNode) {
+      return;
+    }
+
+    if (newParent === null) {
+      const rootBlocks = this.oss.blocks.filter(block => block.parent === null).map(block => block.nodeID);
+      const blocksPositions = this.layout.filter(pos => rootBlocks.includes(pos.nodeID));
+      if (blocksPositions.length === 0) {
+        return;
+      }
+
+      const operationPositions = this.layout.filter(pos => pos.nodeID.startsWith('o') && pos.nodeID !== `o${targetID}`);
+      const newRect = preventOverlap(targetNode, [...blocksPositions, ...operationPositions]);
+      targetNode.x = newRect.x;
+      targetNode.y = newRect.y;
+      return;
+    } else {
+      const parentNode = this.layout.find(pos => pos.nodeID === `b${newParent}`);
+      if (!parentNode) {
+        return;
+      }
+      if (rectanglesOverlap(parentNode, targetNode)) {
+        return;
+      }
+
+      // TODO: fix position based on parent
+    }
   }
 
   /** Update layout when parent changes */
@@ -142,17 +168,16 @@ export class LayoutManager {
   }
 
   private calculatePositionForFreeOperation(initial: Position2D): Position2D {
-    const operations = this.layout.operations;
-    if (operations.length === 0) {
+    if (this.oss.operations.length === 0) {
       return initial;
     }
 
     const freeInputs = this.oss.operations
       .filter(operation => operation.arguments.length === 0 && operation.parent === null)
-      .map(operation => operation.id);
-    let inputsPositions = operations.filter(pos => freeInputs.includes(pos.id));
+      .map(operation => operation.nodeID);
+    let inputsPositions = this.layout.filter(pos => freeInputs.includes(pos.nodeID));
     if (inputsPositions.length === 0) {
-      inputsPositions = operations;
+      inputsPositions = this.layout.filter(pos => pos.nodeID.startsWith('o'));
     }
     const maxX = Math.max(...inputsPositions.map(node => node.x));
     const minY = Math.min(...inputsPositions.map(node => node.y));
@@ -163,8 +188,8 @@ export class LayoutManager {
   }
 
   private calculatePositionForFreeBlock(initial: Rectangle2D): Rectangle2D {
-    const rootBlocks = this.oss.blocks.filter(block => block.parent === null).map(block => block.id);
-    const blocksPositions = this.layout.blocks.filter(pos => rootBlocks.includes(pos.id));
+    const rootBlocks = this.oss.blocks.filter(block => block.parent === null).map(block => block.nodeID);
+    const blocksPositions = this.layout.filter(pos => rootBlocks.includes(pos.nodeID));
     if (blocksPositions.length === 0) {
       return initial;
     }
@@ -211,11 +236,10 @@ function preventOverlap(target: Rectangle2D, fixedRectangles: Rectangle2D[]): Re
   return target;
 }
 
-function calculatePositionFromArgs(args: number[], operations: IOperationPosition[]): Position2D {
-  const argNodes = operations.filter(pos => args.includes(pos.id));
-  const maxY = Math.max(...argNodes.map(node => node.y));
-  const minX = Math.min(...argNodes.map(node => node.x));
-  const maxX = Math.max(...argNodes.map(node => node.x));
+function calculatePositionFromArgs(args: INodePosition[]): Position2D {
+  const maxY = Math.max(...args.map(node => node.y));
+  const minX = Math.min(...args.map(node => node.x));
+  const maxX = Math.max(...args.map(node => node.x));
   return {
     x: Math.ceil((maxX + minX) / 2 / GRID_SIZE) * GRID_SIZE,
     y: maxY + 2 * OPERATION_NODE_HEIGHT + MIN_DISTANCE
@@ -224,8 +248,8 @@ function calculatePositionFromArgs(args: number[], operations: IOperationPositio
 
 function calculatePositionFromChildren(
   initial: Rectangle2D,
-  operations: IOperationPosition[],
-  blocks: IBlockPosition[]
+  operations: INodePosition[],
+  blocks: INodePosition[]
 ): Rectangle2D {
   let left = undefined;
   let top = undefined;
@@ -249,11 +273,11 @@ function calculatePositionFromChildren(
     top = top === undefined ? operation.y - MIN_DISTANCE : Math.min(top, operation.y - MIN_DISTANCE);
     right =
       right === undefined
-        ? Math.max(left + initial.width, operation.x + OPERATION_NODE_WIDTH + MIN_DISTANCE)
-        : Math.max(right, operation.x + OPERATION_NODE_WIDTH + MIN_DISTANCE);
+        ? Math.max(left + initial.width, operation.x + operation.width + MIN_DISTANCE)
+        : Math.max(right, operation.x + operation.width + MIN_DISTANCE);
     bottom = !bottom
-      ? Math.max(top + initial.height, operation.y + OPERATION_NODE_HEIGHT + MIN_DISTANCE)
-      : Math.max(bottom, operation.y + OPERATION_NODE_HEIGHT + MIN_DISTANCE);
+      ? Math.max(top + initial.height, operation.y + operation.height + MIN_DISTANCE)
+      : Math.max(bottom, operation.y + operation.height + MIN_DISTANCE);
   }
 
   return {
diff --git a/rsconcept/frontend/src/features/oss/pages/oss-page/editor-oss-graph/use-get-layout.tsx b/rsconcept/frontend/src/features/oss/pages/oss-page/editor-oss-graph/use-get-layout.tsx
index 87b23bec..02624e70 100644
--- a/rsconcept/frontend/src/features/oss/pages/oss-page/editor-oss-graph/use-get-layout.tsx
+++ b/rsconcept/frontend/src/features/oss/pages/oss-page/editor-oss-graph/use-get-layout.tsx
@@ -3,6 +3,7 @@ import { type Node, useReactFlow } from 'reactflow';
 import { type IOssLayout } from '../../../backend/types';
 import { type IOperationSchema } from '../../../models/oss';
 import { type Position2D } from '../../../models/oss-layout';
+import { OPERATION_NODE_HEIGHT, OPERATION_NODE_WIDTH } from '../../../models/oss-layout-api';
 import { useOssEdit } from '../oss-edit-context';
 
 import { BLOCK_NODE_MIN_HEIGHT, BLOCK_NODE_MIN_WIDTH } from './graph/block-node';
@@ -14,22 +15,24 @@ export function useGetLayout() {
   return function getLayout(): IOssLayout {
     const nodes = getNodes();
     const nodeById = new Map(nodes.map(node => [node.id, node]));
-    return {
-      operations: nodes
+    return [
+      ...nodes
         .filter(node => node.type !== 'block')
         .map(node => ({
-          id: schema.itemByNodeID.get(node.id)!.id,
-          ...computeAbsolutePosition(node, schema, nodeById)
+          nodeID: node.id,
+          ...computeAbsolutePosition(node, schema, nodeById),
+          width: OPERATION_NODE_WIDTH,
+          height: OPERATION_NODE_HEIGHT
         })),
-      blocks: nodes
+      ...nodes
         .filter(node => node.type === 'block')
         .map(node => ({
-          id: schema.itemByNodeID.get(node.id)!.id,
+          nodeID: node.id,
           ...computeAbsolutePosition(node, schema, nodeById),
           width: node.width ?? BLOCK_NODE_MIN_WIDTH,
           height: node.height ?? BLOCK_NODE_MIN_HEIGHT
         }))
-    };
+    ];
   };
 }