Viewing from different angles causes the material surface to disappear

I load a gltf model,When I look at it from an angle, it has a piece of material that is invisible,But when I look at it from another angle, it appears again.I try to change the side attribute in gltfLoader,But is not work.Has anyone encountered the same problem?

Without seeing a live example it’s not possible to investigate this issue.

What you can try is to disable view frustum culling as a test. You do this by setting the frustumCulled on the respective object to false.