Index: ps/trunk/binaries/data/mods/_test.sim/globalscripts/test-global-helper.js
===================================================================
--- ps/trunk/binaries/data/mods/_test.sim/globalscripts/test-global-helper.js
+++ ps/trunk/binaries/data/mods/_test.sim/globalscripts/test-global-helper.js
@@ -39,7 +39,3 @@
 	this.z += v.z;
 	return this;
 };
-
-// make the prototypes easily accessible to C++
-const Vector2Dprototype = Vector2D.prototype;
-const Vector3Dprototype = Vector3D.prototype;
Index: ps/trunk/binaries/data/mods/public/globalscripts/vector.js
===================================================================
--- ps/trunk/binaries/data/mods/public/globalscripts/vector.js
+++ ps/trunk/binaries/data/mods/public/globalscripts/vector.js
@@ -429,8 +429,3 @@
 {
 	return new Vector3D(v.x / f, v.y / f, v.z / f);
 };
-
-
-// make the prototypes easily accessible to C++
-const Vector2Dprototype = Vector2D.prototype;
-const Vector3Dprototype = Vector3D.prototype;
Index: ps/trunk/source/scriptinterface/ScriptInterface.h
===================================================================
--- ps/trunk/source/scriptinterface/ScriptInterface.h
+++ ps/trunk/source/scriptinterface/ScriptInterface.h
@@ -115,9 +115,6 @@
 	 */
 	bool LoadGlobalScripts();
 
-	enum CACHED_VAL { CACHE_VECTOR2DPROTO, CACHE_VECTOR3DPROTO };
-	JS::Value GetCachedValue(CACHED_VAL valueIdentifier) const;
-
 	/**
 	 * Replace the default JS random number geenrator with a seeded, network-sync'd one.
 	 */
Index: ps/trunk/source/scriptinterface/ScriptInterface.cpp
===================================================================
--- ps/trunk/source/scriptinterface/ScriptInterface.cpp
+++ ps/trunk/source/scriptinterface/ScriptInterface.cpp
@@ -67,9 +67,6 @@
 	JSCompartment* m_comp;
 	boost::rand48* m_rng;
 	JS::PersistentRootedObject m_nativeScope; // native function scope object
-
-	typedef std::map<ScriptInterface::CACHED_VAL, JS::PersistentRootedValue> ScriptValCache;
-	ScriptValCache m_ScriptValCache;
 };
 
 namespace
@@ -450,13 +447,6 @@
 	return pCxPrivate;
 }
 
-JS::Value ScriptInterface::GetCachedValue(CACHED_VAL valueIdentifier) const
-{
-	std::map<ScriptInterface::CACHED_VAL, JS::PersistentRootedValue>::const_iterator it = m->m_ScriptValCache.find(valueIdentifier);
-	ENSURE(it != m->m_ScriptValCache.end());
-	return it->second.get();
-}
-
 
 bool ScriptInterface::LoadGlobalScripts()
 {
@@ -474,13 +464,6 @@
 			return false;
 		}
 
-	JSAutoRequest rq(m->m_cx);
-	JS::RootedValue proto(m->m_cx);
-	JS::RootedObject global(m->m_cx, m->m_glob);
-	if (JS_GetProperty(m->m_cx, global, "Vector2Dprototype", &proto))
-		m->m_ScriptValCache[CACHE_VECTOR2DPROTO].init(GetJSRuntime(), proto);
-	if (JS_GetProperty(m->m_cx, global, "Vector3Dprototype", &proto))
-		m->m_ScriptValCache[CACHE_VECTOR3DPROTO].init(GetJSRuntime(), proto);
 	return true;
 }
 
Index: ps/trunk/source/simulation2/scripting/EngineScriptConversions.cpp
===================================================================
--- ps/trunk/source/simulation2/scripting/EngineScriptConversions.cpp
+++ ps/trunk/source/simulation2/scripting/EngineScriptConversions.cpp
@@ -32,6 +32,7 @@
 #include "simulation2/system/ParamNode.h"
 
 #define FAIL(msg) STMT(JS_ReportError(cx, msg); return false)
+#define FAILVOID(msg) STMT(JS_ReportError(cx, msg))
 
 template<> void ScriptInterface::ToJSVal<IComponent*>(JSContext* cx, JS::MutableHandleValue ret, IComponent* const& val)
 {
@@ -180,29 +181,19 @@
 {
 	JSAutoRequest rq(cx);
 
-	// apply the Vector3D prototype to the return value;
  	ScriptInterface::CxPrivate* pCxPrivate = ScriptInterface::GetScriptInterfaceAndCBData(cx);
-	JS::RootedObject proto(cx, &pCxPrivate->pScriptInterface->GetCachedValue(ScriptInterface::CACHE_VECTOR3DPROTO).toObject());
-	JS::RootedObject obj(cx, JS_NewObjectWithGivenProto(cx, nullptr, proto));
+	JS::RootedObject global(cx, &pCxPrivate->pScriptInterface->GetGlobalObject().toObject());
+	JS::RootedValue valueVector3D(cx);
+	if (!JS_GetProperty(cx, global, "Vector3D", &valueVector3D))
+		FAILVOID("Failed to get Vector3D constructor");
+
+	JS::AutoValueArray<3> args(cx);
+	args[0].setNumber(val.X.ToDouble());
+	args[1].setNumber(val.Y.ToDouble());
+	args[2].setNumber(val.Z.ToDouble());
 
-	if (!obj)
-	{
-		ret.setUndefined();
-		return;
-	}
-
-	JS::RootedValue x(cx);
-	JS::RootedValue y(cx);
-	JS::RootedValue z(cx);
-	ToJSVal(cx, &x, val.X);
-	ToJSVal(cx, &y, val.Y);
-	ToJSVal(cx, &z, val.Z);
-
-	JS_SetProperty(cx, obj, "x", x);
-	JS_SetProperty(cx, obj, "y", y);
-	JS_SetProperty(cx, obj, "z", z);
-
-	ret.setObject(*obj);
+	if (!JS::Construct(cx, valueVector3D, args, ret))
+		FAILVOID("Failed to construct Vector3D object");
 }
 
 template<> bool ScriptInterface::FromJSVal<CFixedVector2D>(JSContext* cx, JS::HandleValue v, CFixedVector2D& out)
@@ -227,25 +218,18 @@
 {
 	JSAutoRequest rq(cx);
 
-	// apply the Vector2D prototype to the return value
  	ScriptInterface::CxPrivate* pCxPrivate = ScriptInterface::GetScriptInterfaceAndCBData(cx);
-	JS::RootedObject proto(cx, &pCxPrivate->pScriptInterface->GetCachedValue(ScriptInterface::CACHE_VECTOR2DPROTO).toObject());
-	JS::RootedObject obj(cx, JS_NewObjectWithGivenProto(cx, nullptr, proto));
-	if (!obj)
-	{
-		ret.setUndefined();
-		return;
-	}
-
-	JS::RootedValue x(cx);
-	JS::RootedValue y(cx);
-	ToJSVal(cx, &x, val.X);
-	ToJSVal(cx, &y, val.Y);
+	JS::RootedObject global(cx, &pCxPrivate->pScriptInterface->GetGlobalObject().toObject());
+	JS::RootedValue valueVector2D(cx);
+	if (!JS_GetProperty(cx, global, "Vector2D", &valueVector2D))
+		FAILVOID("Failed to get Vector2D constructor");
+
+	JS::AutoValueArray<2> args(cx);
+	args[0].setNumber(val.X.ToDouble());
+	args[1].setNumber(val.Y.ToDouble());
 
-	JS_SetProperty(cx, obj, "x", x);
-	JS_SetProperty(cx, obj, "y", y);
-
-	ret.setObject(*obj);
+	if (!JS::Construct(cx, valueVector2D, args, ret))
+		FAILVOID("Failed to construct Vector2D object");
 }
 
 template<> void ScriptInterface::ToJSVal<Grid<u8> >(JSContext* cx, JS::MutableHandleValue ret, const Grid<u8>& val)