code: function getData( polygonVertexIndex, polygonIndex, vertexIndex, infoObject ) {
  
  		var index;
  
  		switch ( infoObject.mappingType ) {
  
  			case 'ByPolygonVertex' :
  				index = polygonVertexIndex;
  				break;
  			case 'ByPolygon' :
  				index = polygonIndex;
  				break;
  			case 'ByVertice' :
  				index = vertexIndex;
  				break;
  			case 'AllSame' :
  				index = infoObject.indices[ 0 ];
  				break;
  			default :
  				console.warn( 'THREE.FBXLoader: unknown attribute mapping type ' + infoObject.mappingType );
  
  		}
  
  		if ( infoObject.referenceType === 'IndexToDirect' ) index = infoObject.indices[ index ];
  
  		var from = index * infoObject.dataSize;
  		var to = from + infoObject.dataSize;
  
  		return slice( dataArray, infoObject.buffer, from, to );
  
  	}
docs: extracts the data from the correct position in the FBX array based on indexing type