Store blend weight accumulators in the animationCache object that is created by THREE.Animation.

src/extras/animation/Animation.js

@@ -57,20 +57,26 @@ THREE.Animation.prototype.reset = function () {
 
 		if ( object.animationCache === undefined ) {
 
-			object.animationCache = {};
-
+			object.animationCache = {
+				animations: {},
+				blending: {
+					positionWeight: 0.0,
+					quaternionWeight: 0.0,
+					scaleWeight: 0.0
+				}
+			};
 		}
 
-		if ( object.animationCache[this.data.name] === undefined ) {
+		if ( object.animationCache.animations[this.data.name] === undefined ) {
 
-			object.animationCache[this.data.name] = {};
-			object.animationCache[this.data.name].prevKey = { pos: 0, rot: 0, scl: 0 };
-			object.animationCache[this.data.name].nextKey = { pos: 0, rot: 0, scl: 0 };
-			object.animationCache[this.data.name].originalMatrix = object.matrix;
+			object.animationCache.animations[this.data.name] = {};
+			object.animationCache.animations[this.data.name].prevKey = { pos: 0, rot: 0, scl: 0 };
+			object.animationCache.animations[this.data.name].nextKey = { pos: 0, rot: 0, scl: 0 };
+			object.animationCache.animations[this.data.name].originalMatrix = object.matrix;
 
 		}
 
-		var animationCache = object.animationCache[this.data.name];
+		var animationCache = object.animationCache.animations[this.data.name];
 
 		// Get keys to match our current time
 
@@ -97,6 +103,23 @@ THREE.Animation.prototype.reset = function () {
 
 };
 
+THREE.Animation.prototype.resetBlendWeights = function () {
+
+	for ( var h = 0, hl = this.hierarchy.length; h < hl; h ++ ) {
+
+		var object = this.hierarchy[ h ];
+
+		if ( object.animationCache !== undefined ) {
+
+			object.animationCache.blending.positionWeight = 0.0;
+			object.animationCache.blending.quaternionWeight = 0.0;
+			object.animationCache.blending.scaleWeight = 0.0;
+
+		}
+
+	}
+
+};
 
 THREE.Animation.prototype.update = (function(){
 
@@ -175,7 +198,8 @@ THREE.Animation.prototype.update = (function(){
 		for ( var h = 0, hl = this.hierarchy.length; h < hl; h ++ ) {
 
 			var object = this.hierarchy[ h ];
-			var animationCache = object.animationCache[this.data.name];
+			var animationCache = object.animationCache.animations[this.data.name];
+			var blending = object.animationCache.blending;
 
 			// loop through pos/rot/scl
 
@@ -226,9 +250,9 @@ THREE.Animation.prototype.update = (function(){
 						newVector.z = prevXYZ[ 2 ] + ( nextXYZ[ 2 ] - prevXYZ[ 2 ] ) * scale;
 
 						// blend
-						var proportionalWeight = this.weight / ( this.weight + object.accumulatedPosWeight );
+						var proportionalWeight = this.weight / ( this.weight + blending.positionWeight );
 						object.position.lerp( newVector, proportionalWeight );
-						object.accumulatedPosWeight += this.weight;
+						blending.positionWeight += this.weight;
 
 					} else if ( this.interpolationType === THREE.AnimationHandler.CATMULLROM ||
 								this.interpolationType === THREE.AnimationHandler.CATMULLROM_FORWARD ) {
@@ -241,8 +265,8 @@ THREE.Animation.prototype.update = (function(){
 						scale = scale * 0.33 + 0.33;
 
 						var currentPoint = interpolateCatmullRom( points, scale );
-						var proportionalWeight = this.weight / ( this.weight + object.accumulatedPosWeight );
-						object.accumulatedPosWeight += this.weight;
+						var proportionalWeight = this.weight / ( this.weight + blending.positionWeight );
+						blending.positionWeight += this.weight;
 
 						// blend
 
@@ -273,16 +297,16 @@ THREE.Animation.prototype.update = (function(){
 					THREE.Quaternion.slerp( prevXYZ, nextXYZ, newQuat, scale );
 
 					// Avoid paying the cost of an additional slerp if we don't have to
-					if ( object.accumulatedRotWeight === 0 ) {
+					if ( blending.quaternionWeight === 0 ) {
 
 						object.quaternion.copy(newQuat);
-						object.accumulatedRotWeight = this.weight;
+						blending.quaternionWeight = this.weight;
 
 					} else {
 
-						var proportionalWeight = this.weight / ( this.weight + object.accumulatedRotWeight );
+						var proportionalWeight = this.weight / ( this.weight + blending.quaternionWeight );
 						THREE.Quaternion.slerp( object.quaternion, newQuat, object.quaternion, proportionalWeight );
-						object.accumulatedRotWeight += this.weight;
+						blending.quaternionWeight += this.weight;
 
 					}
 
@@ -292,9 +316,9 @@ THREE.Animation.prototype.update = (function(){
 					newVector.y = prevXYZ[ 1 ] + ( nextXYZ[ 1 ] - prevXYZ[ 1 ] ) * scale;
 					newVector.z = prevXYZ[ 2 ] + ( nextXYZ[ 2 ] - prevXYZ[ 2 ] ) * scale;
 
-					var proportionalWeight = this.weight / ( this.weight + object.accumulatedSclWeight);
+					var proportionalWeight = this.weight / ( this.weight + blending.scaleWeight );
 					object.scale.lerp( newVector, proportionalWeight );
-					object.accumulatedSclWeight += this.weight;
+					blending.scaleWeight += this.weight;
 
 				}
 

src/extras/animation/AnimationHandler.js

@@ -191,6 +191,12 @@ THREE.AnimationHandler = {
 
 	update: function ( deltaTimeMS ) {
 
+		for ( var i = 0; i < this.animations.length; i ++ ) {
+
+			this.animations[ i ].resetBlendWeights( );
+
+		}
+
 		for ( var i = 0; i < this.animations.length; i ++ ) {
 
 			this.animations[ i ].update( deltaTimeMS );