Falloff map in Fresnel mode is not supported in Refract IOR slot

This message is triggered when scene contains CoronaMTL that has Falloff map set to Fresnel IOR mode plugged into reflection color slot. For internal architecture reasons, 3ds Max’s Fresnel formula from Falloff node can not be used for GGX BRDF model.


  • Remove Falloff map set to Fresnel IOR from reflection color slot
  • If you need to map Fresnel IOR based on texture, use Fresnel IOR map slot instead