code: function traverseMeshes( cb ) {
  
  			object.traverse( function ( child ) {
  
  				if ( child.isMesh === true ) {
  
  					var mesh = child;
  					var geometry = mesh.geometry;
  
  					if ( geometry.isGeometry === true ) {
  
  						geometry = geomToBufferGeom.get( geometry );
  
  					}
  
  					if ( geometry.isBufferGeometry === true ) {
  
  						if ( geometry.getAttribute( 'position' ) !== undefined ) {
  
  							cb( mesh, geometry );
  
  						}
  
  					}
  
  				}
  
  			} );
  
  		}
docs: Iterate over the valid meshes in the object