Mask a 3D Object using a 3D Volume

I want to make an effect in wich a 3d object can't be visible if another invisible or transparent 3d object is in front of it (like a 2d sprite mask but in 3d objects). I want something like in the example image. I want that only the sphere can be "covered" by the invisible (or transparent) quad, not all objects in the scene, I mean, all objects in the scene can be visible if the quad is in front of it except the sphere.

I fond this that makes exactly what I want https://answers.unity.com/questions/1553334/masking-a-3d-object-using-a-3d-volume.html I prove it and it works! But the next day it stopped working and I don't know anything about shaders code :(

¿Can someone tell me another way to make this effect? ¿Or a way make the effect of the link works again?