title: PBR materials reflectivity decreases after lightmaps are being applied in three.js renderer
body: <p>I'm a 3d artist working on a 3d architectural configurator based on three.js and Gltf. The configurator uses lightmaps. And I'm experiencing an issue when after lightmaps being applied to the model the PBR materials reflectivity globally decreasing. </p>
  
  <p>Here is a screenshot with a model before applying lightmaps on the left and with lightmaps on the right.</p>
  
  <p><a href="https://i.stack.imgur.com/Hjeqe.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Hjeqe.jpg" alt="rendering with and without lightmaps"></a></p>
  
  <p>I wonder if it's possible to have the same reflectivity with lightmaps and without them and where to dig if so. </p>
  
  <p>Thanks!</p>