how to change roughness and light vector?

Development Rendering
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1

hi,i want to only use roughness and base color to get better result.Now I let texture’s red channel to lerp,in the case of direct sunlight can get very good results，but without direct sunlight,i can not see any result.
Is there any way to make me modify the sun and the map’s normal angle in the material editor?Or have better way to achieve this effect

192136-dt[rm)l93lfh6nnvncezr]9.png

2

Do you use any reflection captures actors, like Sphere reflection?

3

I did not use any reflection captures actors,actully in some angles i can not see any effect