Hello

When I use Plot3D to plot the plane I cannot add the 3D points coordinates in the Epilog since it is a known limitation still prevailing with the current 14.2 version.
So I use Show with Plot3D for the plane and Graphics3D to visualize the points and the line through them but no way to get a convincing picture with AspectRatio->Automatic .

I have to adjust recurrently this option manually.

  a={1,2,3};   (* point  on the plane*) 
  p1={3,3,3}; (* points on the line *)
  p2={-2,-2,-2};

-x-y-z+6 = 0 computed equation of the plane by hand

 Show[Plot3D[-x - y + 6, {x, -5, 5}, {y, -5, 5}, 
   AxesLabel -> {x, y, z}], 
  Graphics3D[{Red, PointSize[0.02], Point[a], PointSize[0.02], Blue, 
    Point[p1], Point[p2], Green, Line[{p1, p2}]}, AspectRatio -> 1], 
  PlotRange -> {{-5, 5}, {-5, 5}, {-5, 5}}, AspectRatio -> Automatic]

After some manual iterations, with AspectRatio->1.25 it’s fine.

Is it possible to avoid this manual process and keep Plot3D since there are other functions that I want to plot together?

Thanks