# How do I add a vertical plane in Plot3D?

I use the following code to generate a plot:

a[r_] := A  r^3/( r^3 + A^3 L1^2);
Rg[r_] := (2 ma r^3)/( r^3 + 2 ma^3 L^2);
\[Rho][r_] := r^2 + a[r]^2*Cos[\[Theta]]^2;
\[CapitalDelta][r_] := r^2 - Rg[r] r + a[r]^2;

g = {{-(1 - (Rg[r] r)/\[Rho][r])(*G[r]*), 0,
0, -((a[r] Sin[\[Theta]]^2 r Rg[r])/\[Rho][r])}, {0, \[Rho][
r]/\[CapitalDelta][r], 0, 0}, {0, 0, \[Rho][r],
0}, {-((a[r] Sin[\[Theta]]^2 r Rg[r])/\[Rho][r]), 0, 0,
Sin[\[Theta]]^2 (r^2 + a[r]^2 + (
a[r]^2 Rg[r] r Sin[\[Theta]]^2)/\[Rho][r])}};

v1 = {Sqrt[-(g[[1, 1]] - g[[1, 4]]^2/g[[4, 4]])], 0, 0, 0} ;

(v1.g.v1) /. {A -> 6, ma -> 10, L1 -> 0.1, L -> 0.1};

Plot3D[%,{r,0,20},{\[Theta],0,Pi}]


and I get the plot: Now I want to add a vertical plane at r=18. How can I do that?

• Show[plot, Graphics3D @ InfinitePlane[...]] – Kuba Dec 13 '19 at 10:25
• @Kuba Could you please be more explicit? In the documentation I have found that I should substitute three coordinate points in [...], but I don't get which. I have tried variuos combination, but I always get the same plot that I have reported. – mattiav27 Dec 13 '19 at 10:31
• Have a look at Hyperplane. – b.gates.you.know.what Dec 13 '19 at 10:36

Show[{Plot3D[%, {r, 0, 20}, {\[Theta], 0, Pi}, AxesLabel -> Automatic] 