Merge pull request #13033 from looeee/FBXLoader_add_check_for_empty_curves_v2

FBXLoader: Check for empty curves (again)

examples/js/loaders/FBXLoader.js

@@ -2355,21 +2355,21 @@
 
 		var tracks = [];
 
-		if ( rawTracks.T !== undefined ) {
+		if ( rawTracks.T !== undefined && Object.keys( rawTracks.T.curves ).length > 0 ) {
 
 			var positionTrack = generateVectorTrack( rawTracks.modelName, rawTracks.T.curves, rawTracks.initialPosition, 'position' );
 			if ( positionTrack !== undefined ) tracks.push( positionTrack );
 
 		}
 
-		if ( rawTracks.R !== undefined ) {
+		if ( rawTracks.R !== undefined && Object.keys( rawTracks.R.curves ).length > 0 ) {
 
 			var rotationTrack = generateRotationTrack( rawTracks.modelName, rawTracks.R.curves, rawTracks.initialRotation, rawTracks.preRotations );
 			if ( rotationTrack !== undefined ) tracks.push( rotationTrack );
 
 		}
 
-		if ( rawTracks.S !== undefined ) {
+		if ( rawTracks.S !== undefined && Object.keys( rawTracks.S.curves ).length > 0 ) {
 
 			var scaleTrack = generateVectorTrack( rawTracks.modelName, rawTracks.S.curves, rawTracks.initialScale, 'scale' );
 			if ( scaleTrack !== undefined ) tracks.push( scaleTrack );