diff --git a/src/index.d.ts b/src/index.d.ts
index 07ad7c1..477e129 100644
--- a/src/index.d.ts
+++ b/src/index.d.ts
@@ -1,26 +1,101 @@
 import { Object3D, Material } from 'three';
 
-interface GraphData {
+export interface GraphData {
   nodes: NodeObject[];
   links: LinkObject[];
 }
 
-type NodeObject = object & {
+export type NodeObject = object & {
+  /**
+   *  Node id
+   */
   id?: string | number;
+  /**
+   * the node’s zero-based index into nodes
+   */
+  index?: number;
+  /**
+   * the node’s current x-position.
+   * The position ⟨x[,y[,z]]⟩ may be subsequently modified by forces and by the simulation. 
+   * If either applicable x, y or z is NaN, the 2D position is initialized in a phyllotaxis arrangement, 
+   * so chosen to ensure a deterministic, uniform distribution around the origin.
+   */
   x?: number;
+  /**
+   * the node’s current y-position.
+   * The position ⟨x[,y[,z]]⟩ may be subsequently modified by forces and by the simulation. 
+   * If either applicable x, y or z is NaN, the 2D position is initialized in a phyllotaxis arrangement, 
+   * so chosen to ensure a deterministic, uniform distribution around the origin.
+   */
   y?: number;
+  /**
+   * the node’s current z-position.
+   * The position ⟨x[,y[,z]]⟩ may be subsequently modified by forces and by the simulation. 
+   * If either applicable x, y or z is NaN, the 2D position is initialized in a phyllotaxis arrangement, 
+   * so chosen to ensure a deterministic, uniform distribution around the origin.
+   */
   z?: number;
+  /**
+  * The node’s current x-velocity.
+  * The velocity ⟨vx[,vy[,vz]]⟩ may be subsequently modified by forces and by the simulation. 
+  * If either applicable vx, vy or vz is NaN, the velocity is initialized to ⟨0,0,0⟩
+  * @default 0
+  */
   vx?: number;
+  /**
+  * The node’s current y-velocity.
+  * The velocity ⟨vx[,vy[,vz]]⟩ may be subsequently modified by forces and by the simulation. 
+  * If either applicable vx, vy or vz is NaN, the velocity is initialized to ⟨0,0,0⟩
+  * @default 0
+  */
   vy?: number;
+  /**
+  * The node’s current z-velocity.
+  * The velocity ⟨vx[,vy[,vz]]⟩ may be subsequently modified by forces and by the simulation. 
+  * If either applicable vx, vy or vz is NaN, the velocity is initialized to ⟨0,0,0⟩
+  * @default 0
+  */
   vz?: number;
+  /**
+   * The node’s fixed x-position.
+   * At the end of each tick, after the application of any forces, a node with a defined node.fx has node.x reset to this value and node.vx set to zero.
+   * To unfix a node that was previously fixed, set node.fx to null, or delete this property.
+   * @default undefined
+  */
   fx?: number;
+  /**
+   * The node’s fixed y-position.
+   * At the end of each tick, after the application of any forces and in 2 dimensions or higher, a node with a defined node.fy has node.y reset to this value and node.vy set to zero
+   * To unfix a node that was previously fixed, set node.fy to null, or delete this property.
+   * @default undefined
+  */
   fy?: number;
+  /**
+   * The node’s fixed z-position.
+   * At the end of each tick, after the application of any forces and in 3-dimensions, a node with a defined node.fz has node.z reset to this value and node.vz set to zero. 
+   * To unfix a node that was previously fixed, set node.fz to null, or delete this property.
+   * @default undefined
+  */
   fz?: number;
 };
 
-type LinkObject = object & {
+export type LinkObject = object & {
+  /**
+   * The link’s source node.
+   * When the link force is initialized (or re-initialized, as when the nodes or links change), any link.source property which is not an object is replaced by an object reference to 
+   * the corresponding node with the given identifier.
+   */
   source?: string | number | NodeObject;
+  /**
+   * The link’s target node
+   * When the link force is initialized (or re-initialized, as when the nodes or links change), any link.target property which is not an object is replaced by an object reference to 
+   * the corresponding node with the given identifier.
+   */
   target?: string | number | NodeObject;
+  /**
+   * the zero-based index into links
+   */
+  index?: number;
 };
 
 type Accessor<In, Out> = Out | string | ((obj: In) => Out);