Then select ramp1 node. There are 3 colors, red, green and blue,

Delete one color (square with the cross on the right) and set the remaining two to white and black.

*White is transparent and black is solid.

In viewport you can see placement node. That's placement of your ramp.

Scale it to fit the geometry. It's good to scale it little more than the geometry.

If you render you can see that the objects are sliced, but there is little gradation.