title: How do I flip a lens imported from a catalog in Zemax?
body: <p>I am pretty new to this ray tracing software. It is simple to add custom surfaces and insert lenses from a catalog, but I can't figure out how to flip left-right a component without having to modify each surface manually.</p>
  
  <p>This would be useful for instance using plano-concave lenses for collimation to reduce aberrations.</p>
  
  <p>Can someone help me out? 
  Thanks!</p>