RevolutionPlot3D: get graphics primitives

Question

From this answer, I was able to figure out how to get the graphics primitive from a Plot3D. However, this does not seem to work for a RevolutionPlot3D.

Full context: I am following tutorial 7.10 in "Mathematica Cookbook"

Code snippet (full code below):

c1 = RevolutionPlot3D[{t, -height*2t}, {t, 0, base}] 

How can I extract the graphics primitives? from the plot above?

Full Code

Height = 1; Base = 1; theAxis = {1, 1, 1}; theCenterPoint = {0, 0, 0};

C1 = RevolutionPlot3D[
       {t, -Height*2 t}, {t, 0, Base},
       Mesh -> None
     ][[1]]; (*<- Applying the  [[1]] did not work*)

C2 = Rotate[C1, theAxis[[1]], {1, 0, 0}];(*<- I also tried applying the [[1]] the C1 here instead of in the C1 definition*)

C3 = Rotate[C2, theAxis[[2]], {0, 1, 0}];

C4 = Rotate[C3, theAxis[[3]], {0, 0, 1}];

C5 = Translate[
       C4,
       {theCenterPoint[[1]], theCenterPoint[[2]], theCenterPoint[[3]] + Height*Base}
     ]

Answer 1

Use Cases to extract the GraphicsComplex from the plot:

c1 = RevolutionPlot3D[{t, -1*2 t}, {t, 0, 1}];

gc = Cases[c1, _GraphicsComplex, Infinity];

Now use GeometricTransformation to apply different transformation functions onto the graphics:

Graphics3D[
    {
        gc,
        GeometricTransformation[gc /. _RGBColor :> Red, ReflectionTransform @ {0, 0, 1}],
        GeometricTransformation[gc /. _RGBColor :> Blue,
            RotationTransform[Pi / 2, {1, 0, 0}]
        ],
        GeometricTransformation[gc /. _RGBColor :> Green,
            RotationTransform[(-Pi) / 2, {1, 0, 0}]
        ]
    }
]