diff --git a/indra/newview/app_settings/settings.xml b/indra/newview/app_settings/settings.xml
index bed139d9df..c3fb23750f 100644
--- a/indra/newview/app_settings/settings.xml
+++ b/indra/newview/app_settings/settings.xml
@@ -8060,6 +8060,18 @@
     <real>0</real>
   </map>
 
+  <key>RenderDepthPrePass</key>
+  <map>
+    <key>Comment</key>
+    <string>EXPERIMENTAL: Prime the depth buffer with simple prim geometry before rendering with textures.</string>
+    <key>Persist</key>
+    <integer>1</integer>
+    <key>Type</key>
+    <string>Boolean</string>
+    <key>Value</key>
+    <integer>0</integer>
+  </map>
+  
   <key>RenderDepthOfField</key>
   <map>
     <key>Comment</key>
diff --git a/indra/newview/lldrawable.cpp b/indra/newview/lldrawable.cpp
index 3b55ac4a3b..e06242055c 100644
--- a/indra/newview/lldrawable.cpp
+++ b/indra/newview/lldrawable.cpp
@@ -182,7 +182,7 @@ LLVOVolume* LLDrawable::getVOVolume() const
 
 const LLMatrix4& LLDrawable::getRenderMatrix() const
 { 
-	return isRoot() || isState(LLDrawable::ANIMATED_CHILD) ? getWorldMatrix() : getParent()->getWorldMatrix();
+	return isRoot() ? getWorldMatrix() : getParent()->getWorldMatrix();
 }
 
 BOOL LLDrawable::isLight() const
@@ -538,13 +538,12 @@ F32 LLDrawable::updateXform(BOOL undamped)
 			target_rot = new_rot;
 			target_scale = new_scale;
 		}
-		else
+		else if (mVObjp->getAngularVelocity().isExactlyZero())
 		{
-			// snap to final position
+			// snap to final position (only if no target omega is applied)
 			dist_squared = 0.0f;
-			if (getVOVolume() && !isRoot() && !isState(LLDrawable::ANIMATED_CHILD))
+			if (getVOVolume() && !isRoot())
 			{ //child prim snapping to some position, needs a rebuild
-				setState(LLDrawable::ANIMATED_CHILD);
 				gPipeline.markRebuild(this, LLDrawable::REBUILD_POSITION, TRUE);
 			}
 		}
@@ -558,8 +557,7 @@ F32 LLDrawable::updateXform(BOOL undamped)
 		gPipeline.markRebuild(this, LLDrawable::REBUILD_POSITION, TRUE);
 	}
 	else if (!isRoot() && 
-		 (dist_squared >= MIN_INTERPOLATE_DISTANCE_SQUARED || 
-		 !mVObjp->getAngularVelocity().isExactlyZero() ||
+		 (!mVObjp->getAngularVelocity().isExactlyZero() ||
 		 target_pos != mXform.getPosition() ||
 		 target_rot != mXform.getRotation()))
 	{ //child prim moving relative to parent, tag as needing to be rendered atomically and rebuild
diff --git a/indra/newview/llviewerdisplay.cpp b/indra/newview/llviewerdisplay.cpp
index 0adb187dd2..001d8e184a 100644
--- a/indra/newview/llviewerdisplay.cpp
+++ b/indra/newview/llviewerdisplay.cpp
@@ -889,6 +889,28 @@ void display(BOOL rebuild, F32 zoom_factor, int subfield, BOOL for_snapshot)
 		{
 			LLViewerCamera::sCurCameraID = LLViewerCamera::CAMERA_WORLD;
 			LLMemType mt_rg(LLMemType::MTYPE_DISPLAY_RENDER_GEOM);
+
+			if (gSavedSettings.getBOOL("RenderDepthPrePass") && LLGLSLShader::sNoFixedFunction)
+			{
+				gGL.setColorMask(false, false);
+				
+				U32 types[] = { 
+					LLRenderPass::PASS_SIMPLE, 
+					LLRenderPass::PASS_FULLBRIGHT, 
+					LLRenderPass::PASS_SHINY 
+				};
+
+				U32 num_types = LL_ARRAY_SIZE(types);
+				gOcclusionProgram.bind();
+				for (U32 i = 0; i < num_types; i++)
+				{
+					gPipeline.renderObjects(types[i], LLVertexBuffer::MAP_VERTEX, FALSE);
+				}
+
+				gOcclusionProgram.unbind();
+			}
+
+
 			gGL.setColorMask(true, false);
 			if (LLPipeline::sRenderDeferred && !LLPipeline::sUnderWaterRender)
 			{
diff --git a/indra/newview/llvovolume.cpp b/indra/newview/llvovolume.cpp
index 102fe4bab6..847a3767bc 100644
--- a/indra/newview/llvovolume.cpp
+++ b/indra/newview/llvovolume.cpp
@@ -684,7 +684,7 @@ void LLVOVolume::updateTextures()
 	{
 		updateTextureVirtualSize();
 
-		if (mDrawable.notNull() && !isVisible())
+		if (mDrawable.notNull() && !isVisible() && !mDrawable->isActive())
 		{ //delete vertex buffer to free up some VRAM
 			LLSpatialGroup* group  = mDrawable->getSpatialGroup();
 			if (group)
@@ -1438,7 +1438,7 @@ BOOL LLVOVolume::genBBoxes(BOOL force_global)
 
 	BOOL rebuild = mDrawable->isState(LLDrawable::REBUILD_VOLUME | LLDrawable::REBUILD_POSITION | LLDrawable::REBUILD_RIGGED);
 
-//	bool rigged = false;
+	//	bool rigged = false;
 	LLVolume* volume = mRiggedVolume;
 	if (!volume)
 	{
@@ -1493,7 +1493,7 @@ void LLVOVolume::preRebuild()
 	}
 }
 
-void LLVOVolume::updateRelativeXform()
+void LLVOVolume::updateRelativeXform(bool force_identity)
 {
 	if (mVolumeImpl)
 	{
@@ -1517,14 +1517,14 @@ void LLVOVolume::updateRelativeXform()
 		mRelativeXform.invert();
 		mRelativeXformInvTrans.transpose();
 	}
-	else if (drawable->isActive())
+	else if (drawable->isActive() || force_identity)
 	{				
 		// setup relative transforms
 		LLQuaternion delta_rot;
 		LLVector3 delta_pos, delta_scale;
 		
 		//matrix from local space to parent relative/global space
-		bool use_identity = drawable->isSpatialRoot() || drawable->isState(LLDrawable::ANIMATED_CHILD);
+		bool use_identity = force_identity || drawable->isSpatialRoot();
 		delta_rot = use_identity ? LLQuaternion() : mDrawable->getRotation();
 		delta_pos = use_identity ? LLVector3(0,0,0) : mDrawable->getPosition();
 		delta_scale = mDrawable->getScale();
@@ -3969,7 +3969,14 @@ void LLVolumeGeometryManager::registerFace(LLSpatialGroup* group, LLFace* facep,
 	
 	if (drawable->isActive())
 	{
-		model_mat = &drawable->getRenderMatrix();
+		if (drawable->isState(LLDrawable::ANIMATED_CHILD))
+		{
+			model_mat = &drawable->getWorldMatrix();
+		}
+		else
+		{
+			model_mat = &drawable->getRenderMatrix();
+		}
 	}
 	else
 	{
@@ -4618,6 +4625,11 @@ void LLVolumeGeometryManager::rebuildMesh(LLSpatialGroup* group)
 				LLVOVolume* vobj = drawablep->getVOVolume();
 				vobj->preRebuild();
 
+				if (drawablep->isState(LLDrawable::ANIMATED_CHILD))
+				{
+					vobj->updateRelativeXform(true);
+				}
+
 				LLVolume* volume = vobj->getVolume();
 				for (S32 i = 0; i < drawablep->getNumFaces(); ++i)
 				{
@@ -4637,6 +4649,12 @@ void LLVolumeGeometryManager::rebuildMesh(LLSpatialGroup* group)
 						}
 					}
 				}
+
+				if (drawablep->isState(LLDrawable::ANIMATED_CHILD))
+				{
+					vobj->updateRelativeXform();
+				}
+
 				
 				drawablep->clearState(LLDrawable::REBUILD_ALL);
 			}
@@ -4951,10 +4969,20 @@ void LLVolumeGeometryManager::genDrawInfo(LLSpatialGroup* group, U32 mask, std::
 					LLVOVolume* vobj = drawablep->getVOVolume();
 					LLVolume* volume = vobj->getVolume();
 
+					if (drawablep->isState(LLDrawable::ANIMATED_CHILD))
+					{
+						vobj->updateRelativeXform(true);
+					}
+
 					U32 te_idx = facep->getTEOffset();
 
 					facep->getGeometryVolume(*volume, te_idx, 
 						vobj->getRelativeXform(), vobj->getRelativeXformInvTrans(), index_offset);
+
+					if (drawablep->isState(LLDrawable::ANIMATED_CHILD))
+					{
+						vobj->updateRelativeXform(false);
+					}
 				}
 			}
 
diff --git a/indra/newview/llvovolume.h b/indra/newview/llvovolume.h
index 3cf434dc26..b2873c9894 100644
--- a/indra/newview/llvovolume.h
+++ b/indra/newview/llvovolume.h
@@ -203,7 +203,7 @@ public:
 														  LLAssetType::EType type,
 														  void* user_data, S32 status, LLExtStat ext_status);
 					
-				void	updateRelativeXform();
+				void	updateRelativeXform(bool force_identity = false);
 	/*virtual*/ BOOL	updateGeometry(LLDrawable *drawable);
 	/*virtual*/ void	updateFaceSize(S32 idx);
 	/*virtual*/ BOOL	updateLOD();