Custom Planes
Specify the slices to use for subsampling the volume as equations.
show complete Wolfram Language input
In[2]:=
SliceContourPlot3D[
1/Sqrt[(1 + x)^2 + (1 + y)^2 + z^2] - 1/
Sqrt[(-1 + x)^2 + (-1 + y)^2 + z^2], {x == -1, x == 1, y == -1,
y == 1, z == -1, z == 1}, {x, -2, 2}, {y, -2, 2}, {z, -2, 2},
Contours -> Range[-2.5, 2.5, 0.5], Evaluate@opts]
Out[2]=