Question Cull camera to avoid rendering things under a certain y

Pretty straight-forward question: given a value for the y axis, is it possible to make the camera not render things under this value?

I'm using an orthographic camera (although I don't think it makes any difference).



The image shows an example of what I want, culling things under y = 1.

The rotation of the camera doesn't change this criteria. The part under y = 1 must be seen by other cameras, I just need this effect for a single camera.

 

Maybe use stencils for this?
That way you have an infinite plane at the desired Y location and you switch it to the stencil layer when desired

 

You could use a scissor rect but don't know if there is a way to set it via the camera
https://docs.unity3d.com/ScriptReference/Rendering.CommandBuffer.EnableScissorRect.html

Another alternative would be setting the SV_ClipDistance and SV_CullDistance semantics in the vertex shader. Downside is that you need a custom shader.

You could also render to a smaller render texture first and then copy it.

It may also work to fill the bottom of the depth buffer with 0 (or 1 because of reverse z) before rendering.