diff --git a/src/mol-state/context/event.ts b/src/mol-state/event/dispatcher.ts
similarity index 100%
rename from src/mol-state/context/event.ts
rename to src/mol-state/event/dispatcher.ts
diff --git a/src/mol-state/event/event.ts b/src/mol-state/event/event.ts
new file mode 100644
index 0000000000000000000000000000000000000000..32dcb9a0516c288ed83911bba462598e0372cb0d
--- /dev/null
+++ b/src/mol-state/event/event.ts
@@ -0,0 +1,9 @@
+/**
+ * Copyright (c) 2018 mol* contributors, licensed under MIT, See LICENSE file for more info.
+ *
+ * @author David Sehnal <david.sehnal@gmail.com>
+ */
+
+export interface EventDispatcher {
+    // TODO
+}
\ No newline at end of file
diff --git a/src/mol-state/state.ts b/src/mol-state/state.ts
index 0dc9aa8e4beb3b2ec994479187eb10135f3c51ed..fb65ca6dc04016c58c050c3c159531732256aaa6 100644
--- a/src/mol-state/state.ts
+++ b/src/mol-state/state.ts
@@ -7,9 +7,24 @@
 import { StateObject } from './object';
 import { TransformTree } from './tree/tree';
 import { Transform } from './tree/transform';
+import { Map as ImmutableMap } from 'immutable';
+import { StateContext } from './context/context';
 
-export interface State {
-    tree: TransformTree,
-    objects: Map<Transform.InstanceId, StateObject>,
-    history: TransformTree[]
-}
\ No newline at end of file
+export interface State<ObjectProps = unknown> {
+    definition: State.Definition<ObjectProps>,
+    objects: Map<Transform.InstanceId, StateObject>
+}
+
+export namespace State {
+    export type ObjectProps<P> = ImmutableMap<Transform.InstanceId, P>
+
+    export interface Definition<P = unknown> {
+        tree: TransformTree,
+        // things like object visibility
+        props: ObjectProps<P>
+    }
+
+    export async function update<P>(context: StateContext, old: State<P>, tree: Definition<P>, props?: ObjectProps<P>): Promise<State<P>> {
+        throw 'nyi';
+    }
+}
diff --git a/src/mol-state/transformer/controller.ts b/src/mol-state/transformer/controller.ts
new file mode 100644
index 0000000000000000000000000000000000000000..4d970bf1e035ee3c5a6d75f8a86a7c1f495e2691
--- /dev/null
+++ b/src/mol-state/transformer/controller.ts
@@ -0,0 +1,7 @@
+/**
+ * Copyright (c) 2018 mol* contributors, licensed under MIT, See LICENSE file for more info.
+ *
+ * @author David Sehnal <david.sehnal@gmail.com>
+ */
+
+// TODO: relactive transformer params controller
\ No newline at end of file
diff --git a/src/mol-state/tree/context.ts b/src/mol-state/tree/context.ts
index 8c4bb7c09e470c7eb175ee24c9277b94e4b15348..1c274d8cc9b04844ecf2c6dbeae524a15a7bcc82 100644
--- a/src/mol-state/tree/context.ts
+++ b/src/mol-state/tree/context.ts
@@ -4,7 +4,7 @@
  * @author David Sehnal <david.sehnal@gmail.com>
  */
 
-import { EventDispatcher } from '../context/event';
+import { EventDispatcher } from '../event/event';
 
 export interface TransformContext {
     /** An event dispatcher for executing child tasks. */
diff --git a/src/mol-state/tree/transation.ts b/src/mol-state/tree/transation.ts
index 7c7fe83382a744be37fe5118239b71702aebc60d..e05c32a208b6852f79418070f2052173adc4c847 100644
--- a/src/mol-state/tree/transation.ts
+++ b/src/mol-state/tree/transation.ts
@@ -4,4 +4,6 @@
  * @author David Sehnal <david.sehnal@gmail.com>
  */
 
-// TODO
\ No newline at end of file
+export interface TreeTransaction {
+    
+}
\ No newline at end of file