diff --git a/packages/clay/src/elements/Walls/SimpleWall/example.ts b/packages/clay/src/elements/Walls/SimpleWall/example.ts
index e2f2a91..53febea 100644
--- a/packages/clay/src/elements/Walls/SimpleWall/example.ts
+++ b/packages/clay/src/elements/Walls/SimpleWall/example.ts
@@ -33,6 +33,9 @@ const model = new CLAY.Model();
 model.wasm = { path: "https://unpkg.com/web-ifc@0.0.59/", absolute: true };
 await model.init();
 
+const project = new CLAY.Project(model);
+const site = new CLAY.Site(model, project);
+
 const simpleWallType = new CLAY.SimpleWallType(model);
 
 const wall1 = simpleWallType.addInstance();
@@ -48,6 +51,9 @@ wall2.startPoint = new THREE.Vector2(0, -2);
 wall2.endPoint = new THREE.Vector2(0, 3);
 wall2.update(true);
 
+site.children.add(wall1.attributes.expressID);
+site.children.add(wall2.attributes.expressID);
+
 simpleWallType.addCorner({
   wall1,
   wall2,
@@ -198,23 +204,21 @@ const button = BUI.Component.create<BUI.PanelSection>(() => {
 
 document.body.append(button);
 
-// window.addEventListener("keydown", async (e) => {
-//   if (e.code === "KeyP") {
-//     simpleWallType.attributes = {};
-//     console.log("hey");
-//     if (model._modelID === undefined) {
-//       throw new Error("Malformed model!");
-//     }
-//     // TODO: Fix memory leak
-//     const asdf = model._ifcAPI.SaveModel(model._modelID);
-//
-//     model._ifcAPI.Dispose();
-//     model._ifcAPI = null as any;
-//     model._ifcAPI = new WEBIFC.IfcAPI();
-//
-//     await model.init();
-//     model._modelID = model._ifcAPI.OpenModel(asdf, {
-//       TAPE_SIZE: 5000000, // 5MB
-//     });
-//   }
-// });
+window.addEventListener("keydown", async (e) => {
+  if (e.code === "KeyP") {
+    simpleWallType.attributes = {};
+    console.log("hey");
+    if (model._modelID === undefined) {
+      throw new Error("Malformed model!");
+    }
+    // TODO: Fix memory leak
+    const asdf = model._ifcAPI.SaveModel(model._modelID);
+
+    const a = document.createElement("a");
+    const name = "example.ifc";
+    a.href = URL.createObjectURL(new File([asdf], name));
+    a.download = name;
+    a.click();
+    a.remove();
+  }
+});
diff --git a/packages/clay/src/general/ElementChildren/index.ts b/packages/clay/src/general/ElementChildren/index.ts
new file mode 100644
index 0000000..85b077f
--- /dev/null
+++ b/packages/clay/src/general/ElementChildren/index.ts
@@ -0,0 +1,51 @@
+import { IFC4X3 as IFC, Handle } from "web-ifc";
+import { v4 as uuidv4 } from "uuid";
+import { ClayObject, Model } from "../../core";
+
+export class ElementChildren extends ClayObject {
+  attributes: IFC.IfcRelContainedInSpatialStructure;
+  ids = new Set<number>();
+
+  constructor(
+    model: Model,
+    ownerHistory: IFC.IfcOwnerHistory,
+    element: IFC.IfcSpatialElement,
+  ) {
+    super(model);
+    this.attributes = new IFC.IfcRelContainedInSpatialStructure(
+      new IFC.IfcGloballyUniqueId(uuidv4()),
+      ownerHistory,
+      null,
+      null,
+      [],
+      element,
+    );
+
+    this.update();
+  }
+
+  add(itemID: number) {
+    if (this.ids.has(itemID)) {
+      return;
+    }
+    this.attributes.RelatedElements.push(new Handle(itemID));
+    this.ids.add(itemID);
+    this.update();
+  }
+
+  remove(itemID: number) {
+    if (!this.ids.has(itemID)) {
+      return;
+    }
+    const children = this.attributes.RelatedElements as Handle<any>[];
+    this.attributes.RelatedElements = children.filter(
+      (item) => item.value !== itemID,
+    );
+    this.ids.delete(itemID);
+    this.update();
+  }
+
+  update() {
+    this.model.set(this.attributes);
+  }
+}
diff --git a/packages/clay/src/general/Project/index.ts b/packages/clay/src/general/Project/index.ts
new file mode 100644
index 0000000..bf336a7
--- /dev/null
+++ b/packages/clay/src/general/Project/index.ts
@@ -0,0 +1,123 @@
+import { IFC4X3 as IFC } from "web-ifc";
+import { v4 as uuidv4 } from "uuid";
+import * as THREE from "three";
+import { ClayObject, Model } from "../../core";
+import { ClippingPlaneType } from "../../elements";
+import { IfcUtils } from "../../utils/ifc-utils";
+import { SpatialChildren } from "../SpatialChildren";
+
+export class Project extends ClayObject {
+  attributes: IFC.IfcProject;
+
+  ownerHistory: IFC.IfcOwnerHistory;
+
+  spatialChildren: SpatialChildren;
+
+  constructor(model: Model) {
+    super(model);
+
+    if (!this.model.types.has("clipping-planes")) {
+      this.model.types.set("clipping-planes", new ClippingPlaneType(model));
+    }
+
+    const organization = new IFC.IfcOrganization(
+      null,
+      new IFC.IfcLabel("That Open Company"),
+      null,
+      null,
+      null,
+    );
+
+    const person = new IFC.IfcPerson(
+      null,
+      null,
+      null,
+      null,
+      null,
+      null,
+      null,
+      null,
+    );
+
+    const personAndOrganization = new IFC.IfcPersonAndOrganization(
+      person,
+      organization,
+      null,
+    );
+
+    const application = new IFC.IfcApplication(
+      organization,
+      new IFC.IfcLabel("2.4.0"),
+      new IFC.IfcLabel("CLAY"),
+      new IFC.IfcLabel("CLAY"),
+    );
+
+    this.ownerHistory = new IFC.IfcOwnerHistory(
+      personAndOrganization,
+      application,
+      null,
+      IFC.IfcChangeActionEnum.NOTDEFINED,
+      null,
+      null,
+      null,
+      new IFC.IfcTimeStamp(new Date().getTime()),
+    );
+
+    const context = new IFC.IfcGeometricRepresentationContext(
+      null,
+      null,
+      new IFC.IfcDimensionCount(3),
+      new IFC.IfcReal(1.0e-5),
+      new IFC.IfcAxis2Placement3D(
+        IfcUtils.point(new THREE.Vector3()),
+        null,
+        null,
+      ),
+      null,
+    );
+
+    const lengthUnit = new IFC.IfcSIUnit(
+      IFC.IfcUnitEnum.LENGTHUNIT,
+      null,
+      IFC.IfcSIUnitName.METRE,
+    );
+
+    const areaUnit = new IFC.IfcSIUnit(
+      IFC.IfcUnitEnum.AREAUNIT,
+      null,
+      IFC.IfcSIUnitName.SQUARE_METRE,
+    );
+
+    const volumeUnit = new IFC.IfcSIUnit(
+      IFC.IfcUnitEnum.AREAUNIT,
+      null,
+      IFC.IfcSIUnitName.SQUARE_METRE,
+    );
+
+    const units = new IFC.IfcUnitAssignment([lengthUnit, areaUnit, volumeUnit]);
+
+    this.attributes = new IFC.IfcProject(
+      new IFC.IfcGloballyUniqueId(uuidv4()),
+      this.ownerHistory,
+      null,
+      null,
+      null,
+      null,
+      null,
+      [context],
+      units,
+    );
+
+    this.model.set(this.attributes);
+
+    this.spatialChildren = new SpatialChildren(
+      model,
+      this.ownerHistory,
+      this.attributes,
+    );
+  }
+
+  update(): void {
+    this.model.set(this.attributes);
+  }
+}
diff --git a/packages/clay/src/general/Site/index.ts b/packages/clay/src/general/Site/index.ts
new file mode 100644
index 0000000..622fb01
--- /dev/null
+++ b/packages/clay/src/general/Site/index.ts
@@ -0,0 +1,56 @@
+import { IFC4X3 as IFC } from "web-ifc";
+import { v4 as uuidv4 } from "uuid";
+import { ClayObject, Model } from "../../core";
+import { SpatialChildren } from "../SpatialChildren";
+import { ElementChildren } from "../ElementChildren";
+import { Project } from "../Project";
+import { IfcUtils } from "../../utils/ifc-utils";
+
+export class Site extends ClayObject {
+  attributes: IFC.IfcSite;
+
+  spatialChildren: SpatialChildren;
+
+  children: ElementChildren;
+
+  constructor(model: Model, project: Project) {
+    super(model);
+
+    this.attributes = new IFC.IfcSite(
+      new IFC.IfcGloballyUniqueId(uuidv4()),
+      project.ownerHistory,
+      null,
+      null,
+      null,
+      IfcUtils.localPlacement(),
+      null,
+      null,
+      IFC.IfcElementCompositionEnum.ELEMENT,
+      null,
+      null,
+      null,
+      null,
+      null,
+    );
+
+    this.model.set(this.attributes);
+
+    project.spatialChildren.add(this.attributes.expressID);
+
+    this.spatialChildren = new SpatialChildren(
+      model,
+      project.ownerHistory,
+      this.attributes,
+    );
+
+    this.children = new ElementChildren(
+      model,
+      project.ownerHistory,
+      this.attributes,
+    );
+  }
+
+  update(): void {
+    this.model.set(this.attributes);
+  }
+}
diff --git a/packages/clay/src/general/SpatialChildren/index.ts b/packages/clay/src/general/SpatialChildren/index.ts
new file mode 100644
index 0000000..b44970c
--- /dev/null
+++ b/packages/clay/src/general/SpatialChildren/index.ts
@@ -0,0 +1,51 @@
+import { IFC4X3 as IFC, Handle } from "web-ifc";
+import { v4 as uuidv4 } from "uuid";
+import { ClayObject, Model } from "../../core";
+
+export class SpatialChildren extends ClayObject {
+  attributes: IFC.IfcRelAggregates;
+  ids = new Set<number>();
+
+  constructor(
+    model: Model,
+    ownerHistory: IFC.IfcOwnerHistory,
+    element: IFC.IfcObjectDefinition,
+  ) {
+    super(model);
+    this.attributes = new IFC.IfcRelAggregates(
+      new IFC.IfcGloballyUniqueId(uuidv4()),
+      ownerHistory,
+      null,
+      null,
+      element,
+      [],
+    );
+
+    this.update();
+  }
+
+  add(itemID: number) {
+    if (this.ids.has(itemID)) {
+      return;
+    }
+    this.attributes.RelatedObjects.push(new Handle(itemID));
+    this.ids.add(itemID);
+    this.update();
+  }
+
+  remove(itemID: number) {
+    if (!this.ids.has(itemID)) {
+      return;
+    }
+    const children = this.attributes.RelatedObjects as Handle<any>[];
+    this.attributes.RelatedObjects = children.filter(
+      (item) => item.value !== itemID,
+    );
+    this.ids.delete(itemID);
+    this.update();
+  }
+
+  update() {
+    this.model.set(this.attributes);
+  }
+}
diff --git a/packages/clay/src/general/index.ts b/packages/clay/src/general/index.ts
new file mode 100644
index 0000000..03136a8
--- /dev/null
+++ b/packages/clay/src/general/index.ts
@@ -0,0 +1,4 @@
+export * from "./Project";
+export * from "./Site";
+export * from "./SpatialChildren";
+export * from "./ElementChildren";
diff --git a/packages/clay/src/index.ts b/packages/clay/src/index.ts
index 642eda1..b8ccab6 100644
--- a/packages/clay/src/index.ts
+++ b/packages/clay/src/index.ts
@@ -1,5 +1,6 @@
 export * from "./primitives";
 export * from "./elements";
+export * from "./general";
 export * from "./utils";
 export * from "./elements";
 export * from "./geometries";