In material editor there is no preview...instead of the same black ball

how to resolve it???

just a guess without a screenshot of your materials

  • have you turned on the live updates and previews?

  • If your material is working in your project and only previewing wrong, is it possible that you have published parameters with values of zero by default?

  • Make sure you don’t have too high a value in your metallic input. If that value is too high and there’s not enough light then the material will consume all the light on the surface and look black.

Can you supply a screenshot of your material setup?