a=3;
b=6;
c=Sqrt[b^2-a^2];

fx[s_,t_]:=(a+b*Cos[s])*Cos[t]-c*Sin[s]*Sin[t];
fy[s_,t_]:=(a+b*Cos[s])*Sin[t]+c*Sin[s]*Cos[t];
fz[s_,t_]:=a Sin[s];

gr=ParametricPlot3D[{fx[s,t],fy[s,t],fz[s,t]},{s,0,2Pi+0.01},{t,0,2Pi+0.01},Axes->False,PlotPoints->{300,300},Boxed->False,DisplayFunction->$DisplayFunction]