As explained you can set the background to be ‘white’.
You can also use a grouped white-face on its own layer placed to obscure objects behind the section cut.
Alternatively play with your Fog settings - see Nick Sonder’s work…
Thanks.
Can you tell me where to look for Nick Sonder’s work?
Also, I didn’t express myself clearly. It isn’t the sky and ground that I wanted to turn white (though I would do that also). I wanted to keep other objects past the section plane from showing up. For example a door or window that is on the other side of the section plane.