Reflection effect doesn't work on black background or black mesh

[Bretto]

Inter, epoxy resin (forked) - CodeSandbox

Why doesn’t the effect work over a black background or a black mesh ?

[Lawrence3DPK]

Your sphere is using a mesh Basic Material which doesn’t include the necessary channels for environment reflectivity, try using a MeshStandardMaterial with roughness at 0 and metalness at 0.5…

[prisoner849]

And if you want to control reflectivity, then use MeshPhysicalMaterial.

[Bretto]

Ok thank you