Graphics3D[{Shadows[shadow],  ExampleData[{"Geometry3D","StanfordBunny"}][[1]], SpotLight[White, {{0., -0.4473, 0.4291}, {0,0,0}}, Pi/4, 1], Polygon[ 0.01{{-20,20,-1}, {20,20,-1}, {20,-20,-1}, {-20,-20,-1}}]}, "Lighting"->None] /. {{shadow -> True}, {shadow -> False}} // Column

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Graphics3D[{Shadows[True], Polygon[ {{-5,5,-1}, {5,5,-1}, {5,-5,-1}, {-5,-5,-1}}], White, Cuboid[{-1,-1,-1}, {1,1,1}], Shadows[False], PointLight[Red, {1.5075, 4.1557, 2.6129}, 100], Shadows[True], SpotLight[Cyan, {-2.268, -2.144, 3.1635}]}, "Lighting"->None]

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