diff --git a/example/assets/index.glb b/example/assets/index.glb
index a1b58b6..eab4a05 100644
Binary files a/example/assets/index.glb and b/example/assets/index.glb differ
diff --git a/src/3rd/js/three/util/optimize.js b/src/3rd/js/three/util/optimize.js
new file mode 100644
index 0000000..18a4764
--- /dev/null
+++ b/src/3rd/js/three/util/optimize.js
@@ -0,0 +1,85 @@
+xrf.optimize = (opts) => {
+  opts.animatedObjects = []
+
+  xrf.optimize
+  .checkAnimations(opts)
+  .freezeUnAnimatedObjects(opts)
+  .disableShadows(opts)
+  .disableEmbeddedLights(opts)
+  .removeDuplicateLights()
+}
+
+  // check unused animations
+xrf.optimize.checkAnimations = (opts) => {
+  console.log("TODO: fix freezeUnAnimatedObjects for SRC's")
+  return xrf.optimize
+
+  let {model} = opts
+  model.animations.map( (anim) => {  
+    // collect zombie animations and warn user
+    let zombies = anim.tracks.map( (t) => {
+      let name = t.name.replace(/\..*/,'')
+      let obj  = model.scene.getObjectByName(name)
+      if( !model.scene.getObjectByName(name) ) return {anim:anim.name,obj:name}
+      else opts.animatedObjects.push(name)
+      return undefined
+    })
+    if( zombies.length > 0 ){ // only warn for zombies in main scene (because src-scenes might be filtered anyways)
+      zombies
+      .filter( (z) => z ) // filter out undefined
+      .map( (z) => console.warn(`gltf: object '${z.obj}' not found (anim: '${z.anim}'`) )
+      console.warn(`TIP: remove dots in objectnames in blender (which adds dots when duplicating)`)
+    } 
+  })
+  return xrf.optimize
+}
+
+xrf.optimize.freezeUnAnimatedObjects = (opts) => {
+  console.log("TODO: fix freezeUnAnimatedObjects for SRC's")
+  return xrf.optimize
+
+  let {model}  = opts
+  let scene = model.scene
+  // increase performance by freezing all objects
+  scene.traverse( (n) => n.matrixAutoUpdate = false )
+  // except animated objects and children
+  scene.traverse( (n) => {
+    if( ~opts.animatedObjects.indexOf(n.name) ){
+      n.matrixAutoUpdate = true 
+      n.traverse( (m) => m.matrixAutoUpdate = true )
+    }
+  })
+  return xrf.optimize
+}
+
+xrf.optimize.disableShadows = (opts) => {
+  opts.model.scene.traverse( (n) => {
+    if( n.castShadow !== undefined ) n.castShadow = false
+  })
+  return xrf.optimize
+}
+
+xrf.optimize.disableEmbeddedLights = (opts) => {
+  if( !opts.isSRC ) return xrf.optimize
+  // remove lights from SRC's
+  opts.model.scene.traverse( (n) => {
+    if( n.type.match(/light/i) ) n.remove()
+  })
+  return xrf.optimize
+}
+
+xrf.optimize.removeDuplicateLights = () => {
+  // local/extern src's can cause duplicate lights which tax performance 
+  let lights = {}
+  xrf.scene.traverse( (n) => {
+    if( n.type.match(/light/i) ){
+      if( !lights[n.name] ) lights[n.name] = true 
+      else n.remove()
+    }
+  })
+  return xrf.optimize
+}
+
+xrf.addEventListener('parseModel', (opts) => {
+  xrf.optimize(opts)
+})
diff --git a/src/3rd/js/three/xrf/src.js b/src/3rd/js/three/xrf/src.js
index 8c5dbdf..87066d5 100644
--- a/src/3rd/js/three/xrf/src.js
+++ b/src/3rd/js/three/xrf/src.js
@@ -40,10 +40,11 @@ xrf.frag.src.addModel = (model,url,frag,opts) => {
   }else{
     xrf.frag.src.scale( scene, opts, url )           // scale scene
     mesh.add(scene)
-    xrf.emit('parseModel', {...opts, isSRC:true, scene, model}) 
   }
   // flag everything isSRC & isXRF
   mesh.traverse( (n) => { n.isSRC = n.isXRF = n[ opts.isLocal ? 'isSRCLocal' : 'isSRCExternal' ] = true })
+  
+  xrf.emit('parseModel', {...opts, isSRC:true, scene, model}) 
 }
 
 xrf.frag.src.renderAsPortal = (mesh) => {
diff --git a/src/3rd/js/three/xrf/t.js b/src/3rd/js/three/xrf/t.js
index d1b0e9d..792cc4e 100644
--- a/src/3rd/js/three/xrf/t.js
+++ b/src/3rd/js/three/xrf/t.js
@@ -51,25 +51,6 @@ xrf.addEventListener('parseModel', (opts) => {
     mixer.actions.push( mixer.clipAction( anim, model.scene ) )
   })
 
-  mixer.checkZombies = (animations) => {
-    if( mixer.zombieCheck ) return // fire only once
-    animations.map( (anim) => {  
-      // collect zombie animations and warn user
-      let zombies = anim.tracks.map( (t) => {
-        let name = t.name.replace(/\..*/,'')
-        let obj  = model.scene.getObjectByName(name)
-        return !model.scene.getObjectByName(name) ? {anim:anim.name,obj:name} : undefined 
-      })
-      if( zombies.length > 0 && mixer.i == 0 ){ // only warn for zombies in main scene (because src-scenes might be filtered anyways)
-        zombies
-        .filter( (z) => z ) // filter out undefined
-        .map( (z) => console.warn(`gltf: object '${z.obj}' not found (anim: '${z.anim}'`) )
-        console.warn(`TIP: remove dots in objectnames in blender (which adds dots when duplicating)`)
-      } 
-    })
-    mixer.zombieCheck = true
-  }
-
   mixer.play  = (t) => {
     mixer.isPlaying = t.x !== undefined && t.x != t.y 
     mixer.updateLoop(t)
@@ -118,8 +99,6 @@ xrf.addEventListener('parseModel', (opts) => {
     mixer.update.patched = true
   }
 
-  mixer.checkZombies( model.animations)
-
   // calculate total duration/frame based on longest animation
   mixer.duration  = 0
   if( model.animations.length ){
diff --git a/src/3rd/js/three/xrf/uv.js b/src/3rd/js/three/xrf/uv.js
index 25eab18..d4a55c1 100644
--- a/src/3rd/js/three/xrf/uv.js
+++ b/src/3rd/js/three/xrf/uv.js
@@ -2,24 +2,23 @@ xrf.frag.uv = function(v, opts){
   let { frag, mesh, model, camera, scene, renderer, THREE} = opts
 
   if( !mesh.geometry ) return // nothing to do here
-  if( v.floats.length < 2 ) return console.warn('xrfragment.js: got less than 4 uv values ')
+  if( v.floats.length != 4 ) return console.warn('xrfragment.js: got less than 4 uv values ')
 
   xrf.frag.uv.init(mesh)
   mesh.uv.u      = v.floats[0]
   mesh.uv.v      = v.floats[1]
-  mesh.uv.uspeed = v.floats[2] || 1.0 
+  mesh.uv.uspeed = v.floats[2] || 1.0
   mesh.uv.vspeed = v.floats[3] || 1.0
-  mesh.uv.ushift = v.shift[0]
-  mesh.uv.vshift = v.shift[1]
-  mesh.uv.uloop  = v.shift[2] || false
-  mesh.uv.vloop  = v.shift[3] || false
-  debugger
+  mesh.uv.ushift = v.shift[0]  || v.floats[0] < 0  // negative u is always relative 
+  mesh.uv.vshift = v.shift[1]  || v.floats[1] < 0  // negative v is always relative
+  mesh.uv.uloop  = v.shift[2]  || false
+  mesh.uv.vloop  = v.shift[3]  || false
 
   mesh.onBeforeRender = xrf.frag.uv.scroll
 }
 
 xrf.frag.uv.init = function(mesh){
-  if( !mesh.uv  ) mesh.uv   = {u:0, v:0, uspeed:1, vspeed:1, uloop:false, vloop:false, uv:false, ushift:false,vshift:false}
+  if( !mesh.uv  ) mesh.uv   = {u:0, v:0, uspeed:1, vspeed:1, uloop:false, vloop:false, uv:false}
 
   let uv    = mesh.geometry.getAttribute("uv")
   if( !uv.old ) uv.old = mesh.geometry.getAttribute("uv").clone()
@@ -33,34 +32,43 @@ xrf.frag.uv.scroll = function(){
 
   // translate!
   for( let i = 0; i < uv.count; i++ ){
-    let u         = uv.getX(i)     
-    let v         = uv.getY(i)     
-    let uTarget   = (this.uv.ushift ? u : uv.old.getX(i) ) + this.uv.u
-    let vTarget   = (this.uv.vshift ? v : uv.old.getY(i) ) + this.uv.v
 
-    // scroll U
-    if( this.uv.uloop ){
-      u += this.uv.uspeed * xrf.clock.delta
-    }else{
-      // recover from super-high uv-values due to looped scrolling
-      if( Math.abs(u-uTarget) > 1.0 ) u = uv.old.getX(i)
-      u = u > uTarget ?  u + (this.uv.uspeed * -uTarget ) // -xrf.clock.delta)
-                      :  u + (this.uv.uspeed *  uTarget ) // xrf.clock.delta) 
-      diffU += Math.abs( u - uTarget )  // are we done yet? (non-looping mode)
-    } 
+    if( this.uv.uspeed == 1.0 ) uv.setX(i, this.uv.ushift ? uv.getX(i) + this.uv.u : uv.old.getX(i) + this.uv.u )
+    if( this.uv.vspeed == 1.0 ) uv.setY(i, this.uv.vshift ? uv.getY(i) + this.uv.v : uv.old.getY(i) + this.uv.v )
 
-    // scroll V
-    if( this.uv.vloop ){
-      v += this.uv.vspeed * xrf.clock.delta
-    }else{
-      // recover from super-high uv-values due to looped scrolling
-      if( Math.abs(v-vTarget) > 1.0 ) v = uv.old.getY(i)
-      v = v > vTarget ?  v + (this.uv.vspeed * -vTarget ) // -xrf.clock.delta)
-                      :  v + (this.uv.vspeed *  vTarget ) // xrf.clock.delta) 
-      diffV += Math.abs( v - vTarget )
+    if( this.uv.uloop || this.uv.vloop ){
+      let u         = uv.getX(i)     
+      let v         = uv.getY(i)     
+      let uTarget   = this.uv.ushift ? uv.getX(i) + this.uv.u : uv.old.getX(i) + this.uv.u
+      let vTarget   = this.uv.vshift ? uv.getY(i) + this.uv.v : uv.old.getY(i) + this.uv.v
 
+      // scroll U
+      if( this.uv.uloop ){
+        u += this.uv.uspeed * xrf.clock.delta
+      }else{
+        // *TODO* tween to offset
+        //// recover from super-high uv-values due to looped scrolling
+        //if( Math.abs(u-uTarget) > 10.0 ) u = uv.old.getX(i)
+        //u = u > uTarget ?  u + (this.uv.uspeed * -xrf.clock.delta)
+        //                :  u + (this.uv.uspeed *  xrf.clock.delta) 
+        //diffU += Math.abs( u - uTarget )  // are we done yet? (non-looping mode)
+      } 
+
+      // scroll V
+      if( this.uv.vloop ){
+        v += this.uv.vspeed * xrf.clock.delta
+      }else{
+        // *TODO* tween to offset
+        //// recover from super-high uv-values due to looped scrolling
+        //// recover from super-high uv-values due to looped scrolling
+        //if( Math.abs(v-vTarget) > 10.0 ) v = uv.old.getY(i)
+        //v = v > vTarget ?  v + (this.uv.vspeed * -xrf.clock.delta)
+        //                :  v + (this.uv.vspeed *  xrf.clock.delta) 
+        //diffV += Math.abs( v - vTarget )
+      }
+      uv.setXY(i,u,v)
     }
-    uv.setXY(i,u,v)
+
   }
   uv.needsUpdate = true