docs: function setUpConversion() {
  
  		if ( options.convertUpAxis !== true || colladaUp === options.upAxis ) {
  
  			upConversion = null;
  
  		} else {
  
  			switch ( colladaUp ) {
  
  				case 'X':
  
  					upConversion = options.upAxis === 'Y' ? 'XtoY' : 'XtoZ';
  					break;
  
  				case 'Y':
  
  					upConversion = options.upAxis === 'X' ? 'YtoX' : 'YtoZ';
  					break;
  
  				case 'Z':
  
  					upConversion = options.upAxis === 'X' ? 'ZtoX' : 'ZtoY';
  					break;
  
  			}
  
  		}
  
  	}