diff --git a/flexExtContainer.cpp b/flexExtContainer.cpp
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+++ b/flexExtContainer.cpp
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+// This code contains NVIDIA Confidential Information and is disclosed to you
+// under a form of NVIDIA software license agreement provided separately to you.
+//
+// Notice
+// NVIDIA Corporation and its licensors retain all intellectual property and
+// proprietary rights in and to this software and related documentation and
+// any modifications thereto. Any use, reproduction, disclosure, or
+// distribution of this software and related documentation without an express
+// license agreement from NVIDIA Corporation is strictly prohibited.
+//
+// ALL NVIDIA DESIGN SPECIFICATIONS, CODE ARE PROVIDED "AS IS.". NVIDIA MAKES
+// NO WARRANTIES, EXPRESSED, IMPLIED, STATUTORY, OR OTHERWISE WITH RESPECT TO
+// THE MATERIALS, AND EXPRESSLY DISCLAIMS ALL IMPLIED WARRANTIES OF NONINFRINGEMENT,
+// MERCHANTABILITY, AND FITNESS FOR A PARTICULAR PURPOSE.
+//
+// Information and code furnished is believed to be accurate and reliable.
+// However, NVIDIA Corporation assumes no responsibility for the consequences of use of such
+// information or for any infringement of patents or other rights of third parties that may
+// result from its use. No license is granted by implication or otherwise under any patent
+// or patent rights of NVIDIA Corporation. Details are subject to change without notice.
+// This code supersedes and replaces all information previously supplied.
+// NVIDIA Corporation products are not authorized for use as critical
+// components in life support devices or systems without express written approval of
+// NVIDIA Corporation.
+//
+// Copyright (c) 2013-2017 NVIDIA Corporation. All rights reserved.
+
+#include <vector>
+#include <limits>
+#include <algorithm>
+
+#include "../core/core.h"
+#include "../core/maths.h"
+
+#include "../include/NvFlex.h"
+#include "../include/NvFlexExt.h"
+
+class Bitmap
+{
+public:
+
+	typedef unsigned int Word;
+
+	static const int kWordSize = sizeof(Word)*8;
+
+	Bitmap(int numBits) : mBits((numBits+kWordSize-1)/kWordSize)
+	{
+	}
+
+	inline void Set(int bit)
+	{
+		const int wordIndex = bit/kWordSize;
+		const int bitIndex = bit&(kWordSize-1);
+
+		const Word word = mBits[wordIndex];
+
+		mBits[wordIndex] = word|(1<<bitIndex);
+	}
+
+	inline void Reset(int bit)
+	{
+		const int wordIndex = bit/kWordSize;
+		const int bitIndex = bit&(kWordSize-1);
+
+		const Word word = mBits[wordIndex];
+
+		mBits[wordIndex] = word&~(1<<bitIndex);
+	}
+
+	inline bool IsSet(int bit)
+	{
+		const int wordIndex = bit/kWordSize;
+		const int bitIndex = bit&(kWordSize-1);
+
+		const Word word = mBits[wordIndex];
+
+		return (word & (1<<bitIndex)) != 0;
+	}
+
+private:
+
+	std::vector<Word> mBits;
+};
+
+
+struct NvFlexExtContainer
+{
+	int mMaxParticles;
+	
+	NvFlexSolver* mSolver;
+	NvFlexLibrary* mFlexLib;
+
+	// first n indices 
+	NvFlexVector<int> mActiveList;
+	
+	std::vector<int> mFreeList;
+	std::vector<NvFlexExtInstance*> mInstances;
+
+	// particles
+	NvFlexVector<Vec4> mParticles;
+	NvFlexVector<Vec4> mParticlesRest;
+	NvFlexVector<Vec3> mVelocities;
+	NvFlexVector<int> mPhases;
+	NvFlexVector<Vec4> mNormals;	
+
+	// shapes
+	NvFlexVector<int> mShapeOffsets;
+	NvFlexVector<int> mShapeIndices;
+	NvFlexVector<float> mShapeCoefficients;
+	NvFlexVector<float> mShapePlasticThresholds;
+	NvFlexVector<float> mShapePlasticCreeps;
+	NvFlexVector<Quat> mShapeRotations;
+	NvFlexVector<Vec3> mShapeTranslations;
+	NvFlexVector<Vec3> mShapeRestPositions;
+
+	// springs
+	NvFlexVector<int> mSpringIndices;
+	NvFlexVector<float> mSpringLengths;
+	NvFlexVector<float> mSpringCoefficients;
+
+	// cloth
+	NvFlexVector<int> mTriangleIndices;
+	NvFlexVector<Vec3> mTriangleNormals;	
+
+	NvFlexVector<int> mInflatableStarts;
+	NvFlexVector<int> mInflatableCounts;	
+	NvFlexVector<float> mInflatableRestVolumes;
+	NvFlexVector<float> mInflatableCoefficients;
+	NvFlexVector<float> mInflatableOverPressures;
+
+	// bounds (CPU), stored in a vector to ensure transfers can happen asynchronously
+	NvFlexVector<Vec3> mBoundsLower;
+	NvFlexVector<Vec3> mBoundsUpper;
+
+	// needs compact
+	bool mNeedsCompact;
+	// needs to update active list
+	bool mNeedsActiveListRebuild;
+
+	NvFlexExtContainer(NvFlexLibrary* l) :
+		mMaxParticles(0), mSolver(NULL), mFlexLib(l),
+		mActiveList(l),mParticles(l),mParticlesRest(l),mVelocities(l),
+		mPhases(l),mNormals(l),mShapeOffsets(l),mShapeIndices(l),
+		mShapeCoefficients(l),mShapePlasticThresholds(l),
+		mShapePlasticCreeps(l),mShapeRotations(l),mShapeTranslations(l),
+		mShapeRestPositions(l),mSpringIndices(l),mSpringLengths(l),
+		mSpringCoefficients(l),mTriangleIndices(l),mTriangleNormals(l),
+		mInflatableStarts(l),mInflatableCounts(l),mInflatableRestVolumes(l),
+		mInflatableCoefficients(l),mInflatableOverPressures(l), mBoundsLower(l), mBoundsUpper(l),
+		mNeedsCompact(false), mNeedsActiveListRebuild(false)
+	{}
+};
+
+
+
+namespace
+{
+
+// compacts all constraints into linear arrays
+void CompactObjects(NvFlexExtContainer* c)
+{
+	int totalNumSprings = 0;
+	int totalNumTris = 0;
+	int totalNumShapes = 0;
+	int totalNumShapeIndices = 0;
+
+	bool plasticDeformation = false;
+
+	// pre-calculate array sizes
+	for (size_t i = 0; i < c->mInstances.size(); ++i)
+	{
+		NvFlexExtInstance* inst = c->mInstances[i];
+
+		const NvFlexExtAsset* asset = inst->asset;
+
+		// index into the triangle array for this instance
+		inst->triangleIndex = totalNumTris;
+
+		totalNumSprings += asset->numSprings;
+		totalNumTris += asset->numTriangles;
+
+		totalNumShapeIndices += asset->numShapeIndices;
+		totalNumShapes += asset->numShapes;
+
+		if (asset->shapePlasticThresholds && asset->shapePlasticCreeps)
+		{ 
+			plasticDeformation = true;
+		}
+	}
+
+	//----------------------
+	// map buffers
+
+	// springs
+	c->mSpringIndices.map();
+	c->mSpringLengths.map();
+	c->mSpringCoefficients.map();
+
+	// cloth
+	c->mTriangleIndices.map();
+	c->mTriangleNormals.map();
+
+	// inflatables
+	c->mInflatableStarts.map();
+	c->mInflatableCounts.map();
+	c->mInflatableRestVolumes.map();
+	c->mInflatableCoefficients.map();
+	c->mInflatableOverPressures.map();
+
+	// shapes
+	c->mShapeIndices.map();
+	c->mShapeRestPositions.map();
+	c->mShapeOffsets.map();
+	c->mShapeCoefficients.map();
+
+	c->mShapePlasticThresholds.map();
+	c->mShapePlasticCreeps.map();
+
+	c->mShapeTranslations.map();
+	c->mShapeRotations.map();
+
+	//----------------------
+	// resize buffers
+
+	// springs
+	c->mSpringIndices.resize(totalNumSprings * 2);
+	c->mSpringLengths.resize(totalNumSprings);
+	c->mSpringCoefficients.resize(totalNumSprings);
+
+	// cloth
+	c->mTriangleIndices.resize(totalNumTris * 3);
+	c->mTriangleNormals.resize(totalNumTris);
+
+	// inflatables
+	c->mInflatableStarts.resize(0);
+	c->mInflatableCounts.resize(0);
+	c->mInflatableRestVolumes.resize(0);
+	c->mInflatableCoefficients.resize(0);
+	c->mInflatableOverPressures.resize(0);
+
+	// shapes
+	c->mShapeIndices.resize(totalNumShapeIndices);
+	c->mShapeRestPositions.resize(totalNumShapeIndices);
+	c->mShapeOffsets.resize(1 + totalNumShapes);
+	c->mShapeCoefficients.resize(totalNumShapes);
+
+	if (plasticDeformation) 
+	{
+		c->mShapePlasticThresholds.resize(totalNumShapes);
+		c->mShapePlasticCreeps.resize(totalNumShapes);
+	}
+	else
+	{
+		c->mShapePlasticThresholds.resize(0);
+		c->mShapePlasticCreeps.resize(0);
+	}
+
+	c->mShapeTranslations.resize(totalNumShapes);
+	c->mShapeRotations.resize(totalNumShapes);
+
+	int* __restrict dstSpringIndices = (totalNumSprings) ? &c->mSpringIndices[0] : NULL;
+	float* __restrict dstSpringLengths = (totalNumSprings) ? &c->mSpringLengths[0] : NULL;
+	float* __restrict dstSpringCoefficients = (totalNumSprings) ? &c->mSpringCoefficients[0] : NULL;
+
+	int* __restrict dstTriangleIndices = (totalNumTris) ? &c->mTriangleIndices[0] : NULL;
+
+	int* __restrict dstShapeIndices = (totalNumShapeIndices) ? &c->mShapeIndices[0] : NULL;
+	Vec3* __restrict dstShapeRestPositions = (totalNumShapeIndices) ? &c->mShapeRestPositions[0] : NULL;
+	int* __restrict dstShapeOffsets = (totalNumShapes) ? &c->mShapeOffsets[0] : NULL;
+	float* __restrict dstShapeCoefficients = (totalNumShapes) ? &c->mShapeCoefficients[0] : NULL;
+	float* __restrict dstShapePlasticThresholds = NULL;
+	float* __restrict dstShapePlasticCreeps = NULL;
+	if (plasticDeformation)
+	{
+		dstShapePlasticThresholds = (totalNumShapes) ? &c->mShapePlasticThresholds[0] : NULL;
+		dstShapePlasticCreeps = (totalNumShapes) ? &c->mShapePlasticCreeps[0] : NULL;
+	}
+	Vec3* __restrict dstShapeTranslations = (totalNumShapes) ? &c->mShapeTranslations[0] : NULL;
+	Quat* __restrict dstShapeRotations = (totalNumShapes) ? &c->mShapeRotations[0] : NULL;
+
+	// push leading zero if necessary
+	if (totalNumShapes != 0)
+	{
+		*dstShapeOffsets = 0;
+		++dstShapeOffsets;
+	}
+
+	int shapeIndexOffset = 0;
+	int shapeIndex = 0;
+
+	// go through each instance and update springs, shapes, etc
+	for (size_t i = 0; i < c->mInstances.size(); ++i)
+	{
+		NvFlexExtInstance* inst = c->mInstances[i];
+
+		const NvFlexExtAsset* asset = inst->asset;
+
+		// map indices from the asset to the instance
+		const int* __restrict remap = &inst->particleIndices[0];
+
+		// flatten spring data
+		int numSprings = asset->numSprings;
+		const int numSpringIndices = asset->numSprings * 2;
+		const int* __restrict srcSpringIndices = asset->springIndices;
+
+		for (int i = 0; i < numSpringIndices; ++i)
+		{
+			*dstSpringIndices = remap[*srcSpringIndices];
+
+			++dstSpringIndices;
+			++srcSpringIndices;
+		}
+
+		memcpy(dstSpringLengths, asset->springRestLengths, numSprings*sizeof(float));
+		memcpy(dstSpringCoefficients, asset->springCoefficients, numSprings*sizeof(float));
+
+		dstSpringLengths += numSprings;
+		dstSpringCoefficients += numSprings;
+
+		// shapes
+		if (asset->numShapes)
+		{
+			const int indexOffset = shapeIndexOffset;
+
+			// store start index into shape array
+			inst->shapeIndex = shapeIndex;
+
+			int shapeStart = 0;
+
+			for (int s=0; s < asset->numShapes; ++s)
+			{
+				dstShapeOffsets[shapeIndex] = asset->shapeOffsets[s] + indexOffset;
+				dstShapeCoefficients[shapeIndex]  = asset->shapeCoefficients[s];
+				if (plasticDeformation)
+				{
+					if (asset->shapePlasticThresholds)
+						dstShapePlasticThresholds[shapeIndex] = asset->shapePlasticThresholds[s];
+					else
+						dstShapePlasticThresholds[shapeIndex] = 0.0f;
+
+					if (asset->shapePlasticCreeps)
+						dstShapePlasticCreeps[shapeIndex]  = asset->shapePlasticCreeps[s];
+					else
+						dstShapePlasticCreeps[shapeIndex] = 0.0f;
+				}
+				dstShapeTranslations[shapeIndex]  = Vec3(&inst->shapeTranslations[s*3]);
+				dstShapeRotations[shapeIndex]  = Quat(&inst->shapeRotations[s*4]);
+
+				++shapeIndex;
+
+				const int shapeEnd = asset->shapeOffsets[s];
+
+				for (int i=shapeStart; i < shapeEnd; ++i)
+				{
+					const int currentParticle = asset->shapeIndices[i];
+
+					// remap indices and create local space positions for each shape
+					dstShapeRestPositions[shapeIndexOffset] = Vec3(&asset->particles[currentParticle*4]) - Vec3(&asset->shapeCenters[s*3]);
+					dstShapeIndices[shapeIndexOffset] = remap[asset->shapeIndices[i]];
+
+					++shapeIndexOffset;
+				}
+
+				shapeStart = shapeEnd;
+			}		
+		}
+
+		if (asset->numTriangles)
+		{
+			// triangles
+			const int numTriIndices = asset->numTriangles * 3;
+			const int* __restrict srcTriIndices = asset->triangleIndices;
+
+			for (int i = 0; i < numTriIndices; ++i)
+			{
+				*dstTriangleIndices = remap[*srcTriIndices];
+
+				++dstTriangleIndices;
+				++srcTriIndices;
+			}
+
+			if (asset->inflatable)
+			{
+				c->mInflatableStarts.push_back(inst->triangleIndex);
+				c->mInflatableCounts.push_back(asset->numTriangles);
+				c->mInflatableRestVolumes.push_back(asset->inflatableVolume);
+				c->mInflatableCoefficients.push_back(asset->inflatableStiffness);
+				c->mInflatableOverPressures.push_back(asset->inflatablePressure);
+			}
+		}
+	}
+
+
+	//----------------------
+	// unmap buffers
+
+	// springs
+	c->mSpringIndices.unmap();
+	c->mSpringLengths.unmap();
+	c->mSpringCoefficients.unmap();
+
+	// cloth
+	c->mTriangleIndices.unmap();
+	c->mTriangleNormals.unmap();
+
+	// inflatables
+	c->mInflatableStarts.unmap();
+	c->mInflatableCounts.unmap();
+	c->mInflatableRestVolumes.unmap();
+	c->mInflatableCoefficients.unmap();
+	c->mInflatableOverPressures.unmap();
+
+	// shapes
+	c->mShapeIndices.unmap();
+	c->mShapeRestPositions.unmap();
+	c->mShapeOffsets.unmap();
+	c->mShapeCoefficients.unmap();
+
+	c->mShapePlasticThresholds.unmap();
+	c->mShapePlasticCreeps.unmap();
+
+	c->mShapeTranslations.unmap();
+	c->mShapeRotations.unmap();
+
+	// ----------------------
+	// Flex update
+
+	// springs
+	if (c->mSpringLengths.size())
+		NvFlexSetSprings(c->mSolver, c->mSpringIndices.buffer, c->mSpringLengths.buffer, c->mSpringCoefficients.buffer, int(c->mSpringLengths.size()));
+	else
+		NvFlexSetSprings(c->mSolver, NULL, NULL, NULL, 0);
+
+	// shapes
+	if (c->mShapeCoefficients.size())
+	{
+		NvFlexSetRigids(c->mSolver, c->mShapeOffsets.buffer, c->mShapeIndices.buffer, c->mShapeRestPositions.buffer, NULL, c->mShapeCoefficients.buffer, c->mShapePlasticThresholds.buffer, c->mShapePlasticCreeps.buffer, c->mShapeRotations.buffer, c->mShapeTranslations.buffer, int(c->mShapeCoefficients.size()), c->mShapeIndices.size());
+	}
+	else
+	{
+		c->mShapeRotations.resize(0);
+		c->mShapeTranslations.resize(0);
+
+		NvFlexSetRigids(c->mSolver, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, 0, 0);		
+	}
+
+	// triangles
+	if (c->mTriangleIndices.size())
+		NvFlexSetDynamicTriangles(c->mSolver, c->mTriangleIndices.buffer, NULL, int(c->mTriangleIndices.size()/3));
+	else
+		NvFlexSetDynamicTriangles(c->mSolver, NULL, NULL, 0);
+
+	// inflatables
+	if (c->mInflatableCounts.size())
+		NvFlexSetInflatables(c->mSolver, c->mInflatableStarts.buffer, c->mInflatableCounts.buffer, c->mInflatableRestVolumes.buffer, c->mInflatableOverPressures.buffer, c->mInflatableCoefficients.buffer, int(c->mInflatableCounts.size()));
+	else
+		NvFlexSetInflatables(c->mSolver, NULL, NULL, NULL, NULL, NULL, 0);
+
+	c->mNeedsCompact = false;
+
+}
+
+} // anonymous namespace
+
+
+NvFlexExtContainer* NvFlexExtCreateContainer(NvFlexLibrary* flexLib, NvFlexSolver* solver, int maxParticles)
+{
+	NvFlexExtContainer* c = new NvFlexExtContainer(flexLib);
+
+	c->mSolver = solver;
+	c->mFlexLib = flexLib;
+	c->mMaxParticles = maxParticles;
+
+	// initialize free list
+	c->mFreeList.resize(maxParticles);
+	for (int i=0; i < maxParticles; ++i)
+		c->mFreeList[i] = i;
+
+	c->mActiveList.init(maxParticles);
+	c->mParticles.init(maxParticles);
+	c->mParticlesRest.init(maxParticles);
+	c->mVelocities.init(maxParticles);
+	c->mPhases.init(maxParticles);
+	c->mNormals.init(maxParticles);
+
+
+	// ensure we have the corerct CUDA context set
+	NvFlexAcquireContext(flexLib);
+
+	c->mBoundsLower.init(1);
+	c->mBoundsUpper.init(1);
+
+	NvFlexRestoreContext(flexLib);
+
+	c->mNeedsCompact = false;
+
+	return c;
+}
+
+void NvFlexExtDestroyContainer(NvFlexExtContainer* c)
+{
+	// ensure we have the corerct CUDA context set
+	NvFlexLibrary* lib = c->mFlexLib;
+
+	NvFlexAcquireContext(lib);
+
+	delete c;
+
+	NvFlexRestoreContext(lib);
+
+}
+
+int NvFlexExtAllocParticles(NvFlexExtContainer* c, int n, int* indices)
+{
+	const int numToAlloc = Min(int(c->mFreeList.size()), n);
+	const int start = int(c->mFreeList.size())-numToAlloc;
+
+	if (numToAlloc)
+	{
+		memcpy(indices, &c->mFreeList[start], numToAlloc*sizeof(int));
+		c->mFreeList.resize(start);
+	}
+
+	c->mNeedsActiveListRebuild = true;
+
+	return numToAlloc;
+}
+
+void NvFlexExtFreeParticles(NvFlexExtContainer* c, int n, const int* indices)
+{
+#if _DEBUG
+	for (int i=0; i < n; ++i)
+	{
+		// check valid values
+		assert(indices[i] >= 0 && indices[i] < int(c->mFreeList.capacity()));
+
+		// check for double delete
+		assert(std::find(c->mFreeList.begin(), c->mFreeList.end(), indices[i]) == c->mFreeList.end());
+	}
+#endif
+
+	c->mFreeList.insert(c->mFreeList.end(), indices, indices+n);
+
+	c->mNeedsActiveListRebuild = true;
+}
+
+int NvFlexExtGetActiveList(NvFlexExtContainer* c, int* indices)
+{
+	int count = 0;
+
+	Bitmap inactive(c->mMaxParticles);
+
+	// create bitmap
+	for (size_t i=0; i < c->mFreeList.size(); ++i)
+	{
+		// if this fires then somehow a duplicate has ended up in the free list (double delete)
+		assert(!inactive.IsSet(c->mFreeList[i]));
+
+		inactive.Set(c->mFreeList[i]);
+	}
+
+	// iterate bitmap to find active elements
+	for (int i=0; i < c->mMaxParticles; ++i)
+		if (inactive.IsSet(i) == false)
+			indices[count++] = i;
+
+	return count;
+}
+
+NvFlexExtParticleData NvFlexExtMapParticleData(NvFlexExtContainer* c)
+{
+	NvFlexExtParticleData data;
+
+	c->mParticles.map();
+	c->mParticlesRest.map();
+	c->mVelocities.map();
+	c->mPhases.map();
+	c->mNormals.map();
+
+	c->mBoundsLower.map();
+	c->mBoundsUpper.map();
+
+	if (c->mParticles.size())
+		data.particles = (float*)&c->mParticles[0];
+
+	if (c->mParticlesRest.size())
+		data.restParticles = (float*)&c->mParticlesRest[0];
+
+	if (c->mVelocities.size())
+		data.velocities = (float*)&c->mVelocities[0];
+
+	if (c->mPhases.size())
+		data.phases = (int*)&c->mPhases[0];
+
+	if (c->mNormals.size())
+		data.normals = (float*)&c->mNormals[0];
+
+	data.lower = c->mBoundsLower[0];
+	data.upper = c->mBoundsUpper[0];
+
+	return data;
+}
+
+void NvFlexExtUnmapParticleData(NvFlexExtContainer*c)
+{
+	c->mParticles.unmap();
+	c->mParticlesRest.unmap();
+	c->mVelocities.unmap();
+	c->mPhases.unmap();
+	c->mNormals.unmap();
+
+	c->mBoundsLower.unmap();
+	c->mBoundsUpper.unmap();
+}
+
+NvFlexExtTriangleData NvFlexExtMapTriangleData(NvFlexExtContainer* c)
+{
+	NvFlexExtTriangleData data;
+
+	c->mTriangleIndices.map();
+	c->mTriangleNormals.map();
+	
+	if (c->mTriangleIndices.size())
+		data.indices = &c->mTriangleIndices[0];
+	
+	if (c->mTriangleNormals.size())
+		data.normals = (float*)&c->mTriangleNormals[0];
+
+	return data;
+}
+
+void NvFlexExtUnmapTriangleData(NvFlexExtContainer* c)
+{	
+	c->mTriangleIndices.unmap();
+	c->mTriangleNormals.unmap();
+}
+
+NvFlexExtShapeData NvFlexExtMapShapeData(NvFlexExtContainer* c)
+{
+	NvFlexExtShapeData data;
+
+	c->mShapeRotations.map();
+	c->mShapeTranslations.map();
+
+	if (c->mShapeRotations.size())
+		data.rotations = (float*)&c->mShapeRotations[0];
+
+	if (c->mShapeTranslations.size())
+		data.positions = (float*)&c->mShapeTranslations[0];
+
+	data.n = c->mShapeRotations.size();
+
+	return data;
+}
+
+void NvFlexExtUnmapShapeData(NvFlexExtContainer* c)
+{
+	c->mShapeRotations.unmap();
+	c->mShapeTranslations.unmap();
+}
+
+
+NvFlexExtInstance* NvFlexExtCreateInstance(NvFlexExtContainer* c, NvFlexExtParticleData* particleData, const NvFlexExtAsset* asset, const float* transform, float vx, float vy, float vz, int phase, float invMassScale)
+{	
+	const int numParticles = asset->numParticles;
+
+	// check if asset will fit
+	if (int(c->mFreeList.size()) < numParticles)
+		return NULL;
+
+	NvFlexExtInstance* inst = new NvFlexExtInstance();
+
+	inst->asset = asset;
+	inst->triangleIndex = -1;
+	inst->shapeIndex = -1;
+	inst->inflatableIndex = -1;
+	inst->userData = NULL;
+	inst->numParticles = numParticles;
+	
+	assert(inst->numParticles <= asset->maxParticles);
+
+	// allocate particles for instance
+	inst->particleIndices = new int[asset->maxParticles];
+	int n = NvFlexExtAllocParticles(c, numParticles, &inst->particleIndices[0]);
+	assert(n == numParticles);
+	(void)n;
+
+	c->mInstances.push_back(inst);
+
+	const Matrix44 xform(transform);
+
+	for (int i=0; i < numParticles; ++i)
+	{
+		const int index = inst->particleIndices[i];
+
+		// add transformed particles to the locked particle data
+		((Vec4*)(particleData->particles))[index] = xform*Vec4(Vec3(&asset->particles[i*4]), 1.0f);
+		((Vec4*)(particleData->particles))[index].w = asset->particles[i*4+3]*invMassScale;
+		((Vec4*)(particleData->restParticles))[index] = Vec4(&asset->particles[i*4]);
+
+		((Vec3*)(particleData->velocities))[index] = Vec3(vx, vy, vz);
+		((int*)(particleData->phases))[index] = phase;
+		((Vec4*)(particleData->normals))[index] = Vec4(0.0f);
+	}
+
+	const int numShapes = asset->numShapes;
+
+	// allocate memory for shape transforms
+	Vec3* shapeTranslations = new Vec3[numShapes];
+	Quat* shapeRotations = new Quat[numShapes];
+
+	Quat rotation = Quat(Matrix33(xform.GetAxis(0), xform.GetAxis(1), xform.GetAxis(2)));
+
+	for (int i=0; i < numShapes; ++i)
+	{
+		shapeTranslations[i] = Vec3(xform*Vec4(asset->shapeCenters[i*3+0], asset->shapeCenters[i*3+1], asset->shapeCenters[i*3+2], 1.0));
+		shapeRotations[i] = rotation;
+	}
+
+	inst->shapeTranslations = (float*)shapeTranslations;
+	inst->shapeRotations = (float*)shapeRotations;
+
+	// mark container as dirty
+	c->mNeedsCompact = true;
+	c->mNeedsActiveListRebuild = true;
+
+	return inst;
+}
+
+void NvFlexExtDestroyInstance(NvFlexExtContainer* c, const NvFlexExtInstance* inst)
+{
+	NvFlexExtFreeParticles(c, inst->numParticles, &inst->particleIndices[0]);
+	delete[] inst->particleIndices;
+
+	delete[] inst->shapeRotations;
+	delete[] inst->shapeTranslations;
+
+	// TODO: O(N) remove
+	std::vector<NvFlexExtInstance*>::iterator iter = std::find(c->mInstances.begin(), c->mInstances.end(), inst);
+	assert(iter != c->mInstances.end());
+	c->mInstances.erase(iter);
+
+	c->mNeedsCompact = true;
+	c->mNeedsActiveListRebuild = true;
+
+	delete inst;
+}
+
+void NvFlexExtTickContainer(NvFlexExtContainer* c, float dt, int substeps, bool enableTiming)
+{
+	// update the device
+	NvFlexExtPushToDevice(c);
+
+	// update solver
+	NvFlexUpdateSolver(c->mSolver, dt, substeps, enableTiming);
+
+	// update host
+	NvFlexExtPullFromDevice(c);
+}
+
+void NvFlexExtNotifyAssetChanged(NvFlexExtContainer* c, const NvFlexExtAsset* asset)
+{
+	c->mNeedsCompact = true;
+}
+
+void NvFlexExtPushToDevice(NvFlexExtContainer* c)
+{
+	if (c->mNeedsActiveListRebuild)
+	{
+		// update active list
+		c->mActiveList.map();
+		int n = NvFlexExtGetActiveList(c, &c->mActiveList[0]);		
+		c->mActiveList.unmap();
+
+		NvFlexSetActive(c->mSolver, c->mActiveList.buffer, NULL);
+		NvFlexSetActiveCount(c->mSolver, n);
+
+		c->mNeedsActiveListRebuild = false;
+	}
+
+	// push any changes to solver
+	NvFlexSetParticles(c->mSolver, c->mParticles.buffer, NULL);
+	NvFlexSetRestParticles(c->mSolver, c->mParticlesRest.buffer, NULL);
+
+	NvFlexSetVelocities(c->mSolver, c->mVelocities.buffer, NULL);
+	NvFlexSetPhases(c->mSolver, c->mPhases.buffer, NULL);
+	NvFlexSetNormals(c->mSolver, c->mNormals.buffer, NULL);
+	
+	if (c->mNeedsCompact)
+		CompactObjects(c);
+}
+
+void NvFlexExtPullFromDevice(NvFlexExtContainer* c)
+{
+	// read back particle data
+	NvFlexGetParticles(c->mSolver, c->mParticles.buffer, NULL);
+	NvFlexGetVelocities(c->mSolver, c->mVelocities.buffer, NULL);
+	NvFlexGetPhases(c->mSolver, c->mPhases.buffer, NULL);
+	NvFlexGetNormals(c->mSolver, c->mNormals.buffer, NULL);
+	NvFlexGetBounds(c->mSolver, c->mBoundsLower.buffer, c->mBoundsUpper.buffer);
+
+	// read back shape transforms
+	if (c->mShapeCoefficients.size())
+		NvFlexGetRigids(c->mSolver, NULL, NULL, NULL, NULL, NULL, NULL, NULL, c->mShapeRotations.buffer, c->mShapeTranslations.buffer);
+}
+
+void NvFlexExtUpdateInstances(NvFlexExtContainer* c)
+{
+	c->mShapeTranslations.map();
+	c->mShapeRotations.map();
+
+	for (int i=0; i < int(c->mInstances.size()); ++i)
+	{
+		NvFlexExtInstance* inst = c->mInstances[i];
+
+		// copy data back to per-instance memory from the container's memory
+		const int numShapes = inst->asset->numShapes;
+		const int shapeStart = inst->shapeIndex;
+
+		if (shapeStart == -1)
+			continue;
+
+		for (int s=0; s < numShapes; ++s)
+		{
+			((Vec3*)inst->shapeTranslations)[s] = c->mShapeTranslations[shapeStart + s];
+			((Quat*)inst->shapeRotations)[s] = c->mShapeRotations[shapeStart + s];
+		}		
+	}
+
+	c->mShapeTranslations.unmap();
+	c->mShapeRotations.unmap();
+}
+
+void NvFlexExtDestroyAsset(NvFlexExtAsset* asset)
+{
+	delete[] asset->particles;
+	delete[] asset->springIndices;
+	delete[] asset->springCoefficients;
+	delete[] asset->springRestLengths;
+	delete[] asset->triangleIndices;
+	delete[] asset->shapeIndices;
+	delete[] asset->shapeOffsets;
+	delete[] asset->shapeCenters;
+	delete[] asset->shapeCoefficients;	
+	delete[] asset->shapePlasticThresholds;	
+	delete[] asset->shapePlasticCreeps;	
+
+	delete asset;
+}
+
+