envMap does not corresponding to mesh roughness value

Questions
1

hi, I met a problem a few days ago and still cannot find a solution.
so I want to post here to see if anyone could help me out.
when i set metalness = 1
the metal material will look very dark and reflective and not respond to the roughness change(basically it looks the same no matter what roughness I changed.)
i am using lightmap and envMap without any lights.
other material like wood looks correct to me, the only problem is the metal material.
here is how it looks.

image
image916×581 75.8 KB

image
image1378×1054 38.1 KB

any ideas?

3

Looking at your screenshot, it seems that you have used a CubeTexture with six images as your environment map. So you have loaded it via CubeTextureLoader, right? If so, you have to make sure to use PMREMGenerator to preprocess/prefilter the environment map so it can be properly used with a PBR material. All PBR examples are doing this e.g.: