Esempio n. 1
0
 public static NMatrix GetNMatrix(this FLVER.Bone b)
 {
     return(NMatrix.CreateScale(b.Scale) *
            NMatrix.CreateRotationX(b.Rotation.X) *
            NMatrix.CreateRotationZ(b.Rotation.Z) *
            NMatrix.CreateRotationY(b.Rotation.Y) *
            NMatrix.CreateTranslation(b.Translation));
 }
        public static ImportedAnimation ImportFromAssimpScene(Scene scene,
                                                              AnimationImportSettings settings)
        {
            ImportedAnimation result = new ImportedAnimation();

            var sceneMatrix = NMatrix.Identity;

            if (!settings.FlipQuaternionHandedness)
            {
                sceneMatrix *= NMatrix.CreateScale(-1, 1, 1);
            }

            if (settings.ExistingHavokAnimationTemplate == null)
            {
                throw new NotImplementedException("Reading skeleton/binding from assimp scene not supported yet. Please import using existing havok animation as template.");
            }
            else
            {
                result.hkaSkeleton = settings.ExistingHavokAnimationTemplate.hkaSkeleton;
                result.HkxBoneIndexToTransformTrackMap = settings.ExistingHavokAnimationTemplate.HkxBoneIndexToTransformTrackMap;
                result.TransformTrackIndexToHkxBoneMap = settings.ExistingHavokAnimationTemplate.TransformTrackIndexToHkxBoneMap;
            }



            if (settings.ConvertFromZUp)
            {
                sceneMatrix *= NMatrix.CreateRotationZ((float)(Math.PI));
                sceneMatrix *= NMatrix.CreateRotationX((float)(-Math.PI / 2.0));
            }

            var sceneMatrix_ForRootMotion = NMatrix.CreateScale(NVector3.One * settings.SceneScale) * sceneMatrix;

            if (settings.UseRootMotionScaleOverride)
            {
                sceneMatrix_ForRootMotion = NMatrix.CreateScale(NVector3.One * settings.RootMotionScaleOverride) * sceneMatrix;
            }

            sceneMatrix = NMatrix.CreateScale(NVector3.One * settings.SceneScale) * sceneMatrix;



            foreach (var anim in scene.Animations)
            {
                if (anim.HasNodeAnimations)
                {
                    // Setup framerate.
                    double tickScaler = (settings.ResampleToFramerate / anim.TicksPerSecond);

                    result.Duration = anim.DurationInTicks != 0 ? // Don't divide by 0
                                      (float)(anim.DurationInTicks / anim.TicksPerSecond) : 0;
                    result.FrameDuration = (float)(1 / settings.ResampleToFramerate);

                    //result.Duration += result.FrameDuration;
                    int frameCount = (int)Math.Round(result.Duration / result.FrameDuration);

                    double resampleTickMult = settings.ResampleToFramerate / anim.TicksPerSecond;

                    Dictionary <string, int> transformTrackIndexMapping
                        = new Dictionary <string, int>();

                    List <string> transformTrackNames = new List <string>();

                    // Populate transform track names.
                    foreach (var nodeChannel in anim.NodeAnimationChannels)
                    {
                        if (nodeChannel.NodeName == settings.RootMotionNodeName && settings.ExcludeRootMotionNodeFromTransformTracks)
                        {
                            continue;
                        }

                        transformTrackNames.Add(nodeChannel.NodeName);
                    }

                    result.TransformTrackToBoneIndices.Clear();

                    if (settings.ExistingBoneDefaults != null)
                    {
                        var boneNamesInExistingSkel = settings.ExistingBoneDefaults.Keys.ToList();

                        transformTrackNames = boneNamesInExistingSkel;

                        foreach (var tt in transformTrackNames)
                        {
                            result.TransformTrackToBoneIndices.Add(tt, boneNamesInExistingSkel.IndexOf(tt));
                        }
                    }
                    else
                    {
                        int i = 0;
                        foreach (var t in transformTrackNames)
                        {
                            result.TransformTrackToBoneIndices.Add(t, i++);
                        }
                    }

                    // Populate transform track names.
                    foreach (var nodeChannel in anim.NodeAnimationChannels)
                    {
                        //if (nodeChannel.NodeName == settings.RootMotionNodeName && settings.ExcludeRootMotionNodeFromTransformTracks)
                        //    continue;

                        transformTrackIndexMapping.Add(nodeChannel.NodeName, transformTrackNames.IndexOf(nodeChannel.NodeName));
                    }

                    result.TransformTrackNames = transformTrackNames;

                    result.Frames = new List <ImportedAnimation.Frame>();

                    for (int i = 0; i <= frameCount; i++)
                    {
                        var f = new ImportedAnimation.Frame();
                        for (int j = 0; j < transformTrackNames.Count; j++)
                        {
                            if (settings.ExistingBoneDefaults != null && settings.ExistingBoneDefaults.ContainsKey(transformTrackNames[j]) && settings.InitalizeUnanimatedTracksToTPose)
                            {
                                f.BoneTransforms.Add(settings.ExistingBoneDefaults[transformTrackNames[j]]);
                            }
                            else
                            {
                                f.BoneTransforms.Add(NewBlendableTransform.Identity);
                            }
                        }
                        result.Frames.Add(f);
                    }

                    var rootMotionRotationFrames = new NQuaternion[frameCount + 1];

                    //DEBUGGING
                    var DEBUG_ALL_NODE_NAMES_SORTED = anim.NodeAnimationChannels.Select(n => n.NodeName).OrderBy(n => n).ToList();

                    for (int i = 0; i < anim.NodeAnimationChannelCount; i++)
                    {
                        var nodeChannel = anim.NodeAnimationChannels[i];

                        int lastKeyIndex = -1;

                        bool hasPosition = nodeChannel.HasPositionKeys;
                        bool hasRotation = nodeChannel.HasRotationKeys;
                        bool hasScale    = nodeChannel.HasScalingKeys;

                        if (nodeChannel.NodeName.Contains("$AssimpFbx$_Translation"))
                        {
                            hasPosition = true;
                            hasRotation = false;
                            hasScale    = false;
                        }
                        else if (nodeChannel.NodeName.Contains("$AssimpFbx$_Rotation"))
                        {
                            hasPosition = false;
                            hasRotation = true;
                            hasScale    = false;
                        }
                        else if (nodeChannel.NodeName.Contains("$AssimpFbx$_Scaling"))
                        {
                            hasPosition = false;
                            hasRotation = false;
                            hasScale    = true;
                        }


                        bool isRootMotionNode = nodeChannel.NodeName == settings.RootMotionNodeName || (nodeChannel.NodeName.StartsWith(settings.RootMotionNodeName) && nodeChannel.NodeName.Contains("_$AssimpFbx$_"));
                        if (isRootMotionNode)
                        {
                            if (hasPosition)
                            {
                                lastKeyIndex = -1;
                                foreach (var keyPos in nodeChannel.PositionKeys)
                                {
                                    int frame = (int)Math.Floor(keyPos.Time * resampleTickMult);
                                    result.Frames[frame].RootMotionTranslation =
                                        NVector3.Transform(keyPos.Value.ToNumerics(), sceneMatrix_ForRootMotion);

                                    //if (settings.FlipQuaternionHandedness)
                                    //{
                                    //    result.Frames[frame].RootMotionTranslation.X *= -1;
                                    //}

                                    // Fill in from the last keyframe to this one
                                    for (int f = lastKeyIndex + 1; f <= Math.Min(frame - 1, result.Frames.Count - 1); f++)
                                    {
                                        float lerpS     = 1f * (f - lastKeyIndex) / (frame - lastKeyIndex);
                                        var   blendFrom = result.Frames[lastKeyIndex].RootMotionTranslation;
                                        var   blendTo   = result.Frames[frame].RootMotionTranslation;

                                        result.Frames[f].RootMotionTranslation = NVector3.Lerp(blendFrom, blendTo, lerpS);
                                    }
                                    lastKeyIndex = frame;
                                }
                                // Fill in from last key to end of animation.
                                for (int f = lastKeyIndex + 1; f <= result.Frames.Count - 1; f++)
                                {
                                    result.Frames[f].RootMotionTranslation = result.Frames[lastKeyIndex].RootMotionTranslation;
                                }
                            }


                            if (hasRotation && settings.EnableRotationalRootMotion)
                            {
                                lastKeyIndex = -1;

                                foreach (var keyPos in nodeChannel.RotationKeys)
                                {
                                    int frame = (int)Math.Floor(keyPos.Time * resampleTickMult);

                                    var curFrameRotation = keyPos.Value.ToNumerics();
                                    curFrameRotation.Y *= -1;
                                    curFrameRotation.Z *= -1;

                                    if (settings.FlipQuaternionHandedness)
                                    {
                                        curFrameRotation = SapMath.MirrorQuat(curFrameRotation);
                                    }

                                    if (frame >= 0 && frame < frameCount)
                                    {
                                        rootMotionRotationFrames[frame] = curFrameRotation;
                                    }

                                    // Fill in from the last keyframe to this one
                                    for (int f = lastKeyIndex + 1; f <= Math.Min(frame - 1, result.Frames.Count - 1); f++)
                                    {
                                        float lerpS     = 1f * (f - lastKeyIndex) / (frame - lastKeyIndex);
                                        var   blendFrom = rootMotionRotationFrames[lastKeyIndex];
                                        var   blendTo   = curFrameRotation;

                                        var blended = NQuaternion.Slerp(blendFrom, blendTo, lerpS);
                                        //blended = NQuaternion.Normalize(blended);

                                        rootMotionRotationFrames[f] = blended;
                                    }
                                    lastKeyIndex = frame;
                                }
                                // Fill in from last key to end of animation.
                                for (int f = lastKeyIndex + 1; f <= result.Frames.Count - 1; f++)
                                {
                                    rootMotionRotationFrames[f] = rootMotionRotationFrames[lastKeyIndex];
                                }
                            }
                        }

                        if (isRootMotionNode)
                        {
                            hasPosition = false;
                            hasRotation = !settings.EnableRotationalRootMotion;
                        }

                        if (!(isRootMotionNode && !settings.ExcludeRootMotionNodeFromTransformTracks))
                        {
                            string nodeName = nodeChannel.NodeName;

                            int transformIndex = transformTrackIndexMapping[nodeName];

                            int memeIndex = nodeName.IndexOf("_$AssimpFbx$_");
                            if (memeIndex >= 0)
                            {
                                nodeName = nodeName.Substring(0, memeIndex);
                            }



                            if (transformIndex >= 0 && transformIndex < transformTrackNames.Count)
                            {
                                // TRANSLATION
                                if (hasPosition)
                                {
                                    lastKeyIndex = -1;
                                    foreach (var keyPos in nodeChannel.PositionKeys)
                                    {
                                        int frame = (int)Math.Floor(keyPos.Time * resampleTickMult);

                                        var curFrameTransform = result.Frames[frame].BoneTransforms[transformIndex];
                                        curFrameTransform.Translation = NVector3.Transform(keyPos.Value.ToNumerics(), sceneMatrix);
                                        result.Frames[frame].BoneTransforms[transformIndex] = curFrameTransform;

                                        // Fill in from the last keyframe to this one
                                        for (int f = lastKeyIndex + 1; f <= Math.Min(frame - 1, result.Frames.Count - 1); f++)
                                        {
                                            float lerpS     = 1f * (f - lastKeyIndex) / (frame - lastKeyIndex);
                                            var   blendFrom = result.Frames[lastKeyIndex].BoneTransforms[transformIndex].Translation;
                                            var   blendTo   = curFrameTransform.Translation;

                                            var blended = NVector3.Lerp(blendFrom, blendTo, lerpS);

                                            var copyOfStruct = result.Frames[f].BoneTransforms[transformIndex];
                                            copyOfStruct.Translation = blended;
                                            result.Frames[f].BoneTransforms[transformIndex] = copyOfStruct;
                                        }
                                        lastKeyIndex = frame;
                                    }
                                    // Fill in from last key to end of animation.
                                    for (int f = lastKeyIndex + 1; f <= result.Frames.Count - 1; f++)
                                    {
                                        var x = result.Frames[f].BoneTransforms[transformIndex];
                                        x.Translation = result.Frames[lastKeyIndex].BoneTransforms[transformIndex].Translation;
                                        result.Frames[f].BoneTransforms[transformIndex] = x;
                                    }
                                }



                                // SCALE
                                if (hasScale)
                                {
                                    lastKeyIndex = -1;
                                    foreach (var keyPos in nodeChannel.ScalingKeys)
                                    {
                                        int frame = (int)Math.Floor(keyPos.Time * resampleTickMult);

                                        var curFrameTransform = result.Frames[frame].BoneTransforms[transformIndex];
                                        curFrameTransform.Scale = keyPos.Value.ToNumerics();
                                        result.Frames[frame].BoneTransforms[transformIndex] = curFrameTransform;

                                        // Fill in from the last keyframe to this one
                                        for (int f = lastKeyIndex + 1; f <= Math.Min(frame - 1, result.Frames.Count - 1); f++)
                                        {
                                            float lerpS     = 1f * (f - lastKeyIndex) / (frame - lastKeyIndex);
                                            var   blendFrom = result.Frames[lastKeyIndex].BoneTransforms[transformIndex].Scale;
                                            var   blendTo   = curFrameTransform.Scale;

                                            var blended = NVector3.Lerp(blendFrom, blendTo, lerpS);

                                            var copyOfStruct = result.Frames[f].BoneTransforms[transformIndex];
                                            copyOfStruct.Scale = blended;
                                            result.Frames[f].BoneTransforms[transformIndex] = copyOfStruct;
                                        }
                                        lastKeyIndex = frame;
                                    }
                                    // Fill in from last key to end of animation.
                                    for (int f = lastKeyIndex + 1; f <= result.Frames.Count - 1; f++)
                                    {
                                        var x = result.Frames[f].BoneTransforms[transformIndex];
                                        x.Scale = result.Frames[lastKeyIndex].BoneTransforms[transformIndex].Scale;
                                        result.Frames[f].BoneTransforms[transformIndex] = x;
                                    }
                                }

                                // ROTATION
                                if (hasRotation)
                                {
                                    lastKeyIndex = -1;

                                    foreach (var keyPos in nodeChannel.RotationKeys)
                                    {
                                        int frame = (int)Math.Floor(keyPos.Time * resampleTickMult);

                                        var curFrameTransform = result.Frames[frame].BoneTransforms[transformIndex];
                                        curFrameTransform.Rotation    = keyPos.Value.ToNumerics();
                                        curFrameTransform.Rotation.Y *= -1;
                                        curFrameTransform.Rotation.Z *= -1;

                                        if (settings.FlipQuaternionHandedness)
                                        {
                                            curFrameTransform.Rotation = SapMath.MirrorQuat(curFrameTransform.Rotation);
                                        }

                                        result.Frames[frame].BoneTransforms[transformIndex] = curFrameTransform;

                                        // Fill in from the last keyframe to this one
                                        for (int f = lastKeyIndex + 1; f <= Math.Min(frame - 1, result.Frames.Count - 1); f++)
                                        {
                                            float lerpS     = 1f * (f - lastKeyIndex) / (frame - lastKeyIndex);
                                            var   blendFrom = result.Frames[lastKeyIndex].BoneTransforms[transformIndex].Rotation;
                                            var   blendTo   = curFrameTransform.Rotation;

                                            var blended = NQuaternion.Slerp(blendFrom, blendTo, lerpS);
                                            //blended = NQuaternion.Normalize(blended);

                                            var copyOfStruct = result.Frames[f].BoneTransforms[transformIndex];
                                            copyOfStruct.Rotation = blended;

                                            result.Frames[f].BoneTransforms[transformIndex] = copyOfStruct;
                                        }
                                        lastKeyIndex = frame;
                                    }
                                    // Fill in from last key to end of animation.
                                    for (int f = lastKeyIndex + 1; f <= result.Frames.Count - 1; f++)
                                    {
                                        var x = result.Frames[f].BoneTransforms[transformIndex];
                                        x.Rotation = result.Frames[lastKeyIndex].BoneTransforms[transformIndex].Rotation;
                                        result.Frames[f].BoneTransforms[transformIndex] = x;
                                    }
                                }
                            }
                            else
                            {
                                Console.WriteLine("unmapped transform track.");
                            }
                        }
                    }

                    if (settings.BonesToFlipBackwardsAboutYAxis.Count > 0)
                    {
                        var trackIndicesToFlip = result.TransformTrackNames
                                                 .Select((x, i) => i)
                                                 .Where(x => settings.BonesToFlipBackwardsAboutYAxis.Contains(result.TransformTrackNames[x]))
                                                 .ToList();

                        foreach (var f in result.Frames)
                        {
                            foreach (var i in trackIndicesToFlip)
                            {
                                var t = f.BoneTransforms[i];
                                t.Rotation          = NQuaternion.CreateFromRotationMatrix(NMatrix.CreateFromQuaternion(f.BoneTransforms[i].Rotation) * NMatrix.CreateRotationY(SapMath.Pi));
                                t.Translation       = NVector3.Transform(t.Translation, NMatrix.CreateRotationY(SapMath.Pi));
                                f.BoneTransforms[i] = t;
                            }
                        }
                    }

                    result.FrameCount = frameCount;

                    result.Name = anim.Name ?? settings.ExistingHavokAnimationTemplate?.Name ?? "SAP Custom Animation";


                    float rootMotionRot = 0;
                    for (int f = 0; f < result.Frames.Count; f++)
                    {
                        if (f > 0 && settings.EnableRotationalRootMotion)
                        {
                            var curMat = NMatrix.CreateFromQuaternion(rootMotionRotationFrames[f]);
                            var oldMat = NMatrix.CreateFromQuaternion(rootMotionRotationFrames[f - 1]);
                            if (NMatrix.Invert(oldMat, out NMatrix inverseOldMat))
                            {
                                var   deltaMat   = curMat * inverseOldMat;
                                var   deltaVec   = NVector3.Transform(NVector3.UnitX, deltaMat);
                                float deltaAngle = (float)Math.Atan2(deltaVec.Z, deltaVec.X);
                                rootMotionRot += deltaAngle;
                            }
                        }
                        result.Frames[f].RootMotionRotation = rootMotionRot;
                    }

                    break;
                }
            }

            result.RootMotion = new RootMotionData(
                new NVector4(0, 1, 0, 0),
                new NVector4(0, 0, 1, 0),
                result.Duration, result.Frames.Select(f => f.RootMotion).ToArray());

            // Copy first frame for loop?
            //for (int i = 0; i < result.TransformTrackNames.Count; i++)
            //{
            //    result.Frames[result.Frames.Count - 1].BoneTransforms[i] = result.Frames[0].BoneTransforms[i];
            //}

            var rootMotionStart = result.Frames[0].RootMotion;

            for (int i = 0; i < result.Frames.Count; i++)
            {
                result.Frames[i].RootMotionTranslation.X -= rootMotionStart.X;
                result.Frames[i].RootMotionTranslation.Y -= rootMotionStart.Y;
                result.Frames[i].RootMotionTranslation.Z -= rootMotionStart.Z;
                result.Frames[i].RootMotionRotation      -= rootMotionStart.W;

                var xyz = NVector3.Transform(result.Frames[i].RootMotion.XYZ(), NMatrix.CreateRotationY(-rootMotionStart.W));
                result.Frames[i].RootMotionTranslation.X = xyz.X;
                result.Frames[i].RootMotionTranslation.Y = xyz.Y;
                result.Frames[i].RootMotionTranslation.Z = xyz.Z;



                //for (int t = 0; t < result.Frames[i].BoneTransforms.Count; t++)
                //{
                //    if (i > 0 && NQuaternion.Dot(result.Frames[i - 1].BoneTransforms[t].Rotation, result.Frames[i].BoneTransforms[t].Rotation) < 0.995)
                //    {
                //        var tf = result.Frames[i].BoneTransforms[t];
                //        tf.Rotation = NQuaternion.Conjugate(result.Frames[i].BoneTransforms[t].Rotation);
                //        result.Frames[i].BoneTransforms[t] = tf;
                //    }
                //}
            }



            // HOTFIX FOR BAD FBX
            if (result.Frames.Count >= 3)
            {
                result.Frames[result.Frames.Count - 1].RootMotionRotation = result.Frames[result.Frames.Count - 2].RootMotionRotation +
                                                                            (result.Frames[result.Frames.Count - 2].RootMotionRotation - result.Frames[result.Frames.Count - 3].RootMotionRotation);
            }



            //var endFrame = new ImportedAnimation.Frame();
            //foreach (var t in result.Frames[0].BoneTransforms)
            //{
            //    endFrame.BoneTransforms.Add(t);
            //}
            //endFrame.RootMotionTranslation = result.Frames[result.Frames.Count - 1].RootMotionTranslation +
            //    (result.Frames[result.Frames.Count - 1].RootMotionTranslation - result.Frames[result.Frames.Count - 2].RootMotionTranslation);

            //endFrame.RootMotionRotation = result.Frames[result.Frames.Count - 1].RootMotionRotation +
            //    (result.Frames[result.Frames.Count - 1].RootMotionRotation - result.Frames[result.Frames.Count - 2].RootMotionRotation);
            ////endFrame.RootMotionRotation = result.Frames[result.Frames.Count - 1].RootMotionRotation;

            //result.Frames.Add(endFrame);

            return(result);
        }
Esempio n. 3
0
        public static FLVERMetaskeleton GenerateFlverMetaskeletonFromRootNode(
            Node rootNode, Matrix4x4 rootNodeAbsoluteMatrix, float importScale)
        {
            var bonesAssimp          = new List <Node>();
            var skel                 = new FLVERMetaskeleton();
            var dummyAttachBoneNames = new List <string>();

            NMatrix matrixScale = NMatrix.CreateScale(importScale, importScale, importScale);

            // Returns index of bone in master bone list if boneNode is a bone.
            // Returns -1 if boneNode is a DummyPoly (denoted with a node name starting with "DUMMY_POLY").
            int AddBone(Node boneNode, Node parentBoneNode, Matrix4x4 parentAbsoluteMatrix)
            {
                short parentBoneIndex = (short)(bonesAssimp.IndexOf(parentBoneNode));

                var thisBoneMatrix         = boneNode.Transform;
                var thisNodeAbsoluteMatrix = thisBoneMatrix * parentAbsoluteMatrix;


                var boneTrans = FLVERBoneTransform.FromMatrix4x4(
                    (parentBoneIndex == -1 ? thisNodeAbsoluteMatrix : thisBoneMatrix), true);

                if (boneNode.Name.StartsWith("DUMMY_POLY"))
                {
                    // TODO

                    thisNodeAbsoluteMatrix.Decompose(out Vector3D dummyScale, out Quaternion dummyQuat, out Vector3D dummyTranslation);
                    var dmy = new FLVER.Dummy();
                    dmy.ParentBoneIndex = parentBoneIndex;
                    dmy.Position        = dummyTranslation.ToNumerics();

                    // Format: "DUMMY_POLY|<RefID>|<AttachBoneName>"
                    // Example: "DUMMY_POLY|220|Spine1"
                    string[] dummyNameParts = boneNode.Name.Split('|');

                    //ErrorTODO: TryParse
                    dmy.ReferenceID = short.Parse(dummyNameParts[1].Trim());

                    if (dummyNameParts.Length == 3)
                    {
                        dummyAttachBoneNames.Add(dummyNameParts[2]);
                    }
                    else
                    {
                        dummyAttachBoneNames.Add(null);
                    }

                    //NOTE: Maybe this should be specifiable? I forget what the point of false is here.
                    dmy.UseUpwardVector = true;

                    var sceneRotation = NMatrix.CreateRotationX(boneTrans.Rotation.X) *
                                        NMatrix.CreateRotationZ(boneTrans.Rotation.Z) *
                                        NMatrix.CreateRotationY(boneTrans.Rotation.Y);

                    dmy.Upward = NVector3.Transform(new NVector3(0, 1, 0), sceneRotation);
                    //TODO: Check if forward vector3 should be 1 or -1;
                    dmy.Forward = NVector3.Transform(new NVector3(0, 0, 1), sceneRotation);

                    skel.DummyPoly.Add(dmy);

                    return(-1);
                }
                else
                {
                    bonesAssimp.Add(boneNode);

                    int thisBoneIndex = bonesAssimp.Count - 1;

                    var flverBone = new FLVER.Bone();

                    if (parentBoneNode != null)
                    {
                        flverBone.ParentIndex = parentBoneIndex;
                    }

                    flverBone.Name           = boneNode.Name;
                    flverBone.BoundingBoxMin = new NVector3(float.MaxValue, float.MaxValue, float.MaxValue);
                    flverBone.BoundingBoxMax = new NVector3(float.MinValue, float.MinValue, float.MinValue);
                    flverBone.Translation    = boneTrans.Translation * importScale;
                    flverBone.Rotation       = boneTrans.Rotation;
                    flverBone.Scale          = boneTrans.Scale;

                    skel.Bones.Add(flverBone);

                    List <int> childBoneIndices = new List <int>();

                    foreach (var c in boneNode.Children)
                    {
                        int cIndex = AddBone(c, boneNode, thisNodeAbsoluteMatrix);

                        //cIndex will be -1 if the child node was a DummyPoly instead of a bone.
                        if (cIndex >= 0)
                        {
                            childBoneIndices.Add(cIndex);
                        }
                    }

                    if (childBoneIndices.Count > 0)
                    {
                        flverBone.ChildIndex = (short)childBoneIndices[0];

                        for (int i = 0; i < childBoneIndices.Count; i++)
                        {
                            var thisChildBone = skel.Bones[childBoneIndices[i]];
                            if (i == 0)
                            {
                                thisChildBone.PreviousSiblingIndex = -1;
                            }
                            else
                            {
                                thisChildBone.PreviousSiblingIndex = (short)(childBoneIndices[i - 1]);
                            }

                            if (i == childBoneIndices.Count - 1)
                            {
                                thisChildBone.NextSiblingIndex = -1;
                            }
                            else
                            {
                                thisChildBone.NextSiblingIndex = (short)(childBoneIndices[i + 1]);
                            }
                        }
                    }

                    return(thisBoneIndex);
                }
            }

            //if (rootNode.Children == null)
            //    throw new InvalidDataException("Assimp scene has no heirarchy.");

            var root = rootNode;

            //var master = root.Children[0];
            //foreach (var c in root.Children)
            //{
            //    AddBone(c, null, root.Transform * rootNodeAbsoluteMatrix);
            //}
            AddBone(root, null, rootNodeAbsoluteMatrix);
            // Apply parent bone transforms to DummyPoly
            foreach (var d in skel.DummyPoly)
            {
                if (d.ParentBoneIndex >= 0)
                {
                    var parentMat = skel.Bones[d.ParentBoneIndex].GetAbsoluteNMatrix(skel.Bones);
                    d.Position = NVector3.Transform(d.Position, parentMat);
                    d.Upward   = NVector3.TransformNormal(d.Upward, parentMat);
                    d.Forward  = NVector3.TransformNormal(d.Forward, parentMat);
                }
            }

            return(skel);
        }