I'm trying to put this solid
S1 = RegionPlot3D[z - 50 <= -2 x^2 - 2 y^2, {x, -5, 5}, {y, -5, 5}, {z, 0, 50}]
on top of this one
S2 =
RegionPlot3D[x^2 + y^2 <= 50 , {x, -10, 10}, {y, -10, 10}, {z, -50, 0},
PlotStyle -> RGBColor[0.15, 0.17, 0], Mesh -> None]
and it's just kind of smashing it into this
Show[
RegionPlot3D[
z <= -2 x^2 - 2 y^2 && z <= 8 x + y - 20,
{x, -10, 10}, {y, -10, 10}, {z, -100, 0}],
RegionPlot3D[x^2 + y^2 <= 50 , {x, -10, 10}, {y, -10, 10}, {z, -500, -100},
PlotStyle -> RGBColor[0.15, 0.17, 0], Mesh -> None]]
How to combine these 3D plots correctly?