軸も含めるとこんな感じかな
ParametricPlot3D[{r*Sin[t]/2, -r*Cos[t]/4 + 3 r/4 - 1/2,
Sqrt[3]*r*Cos[t]/4 + Sqrt[3]*r/4}, {r, 0, 1}, {t, 0, 2*Pi},
ViewPoint -> All, PlotRange -> All, AxesOrigin -> {0, 0, 0},
Mesh -> False, Boxed -> False]