Wipeout command: How to access View Background colour / gradient?

Hi @stuart.crake,
Here is a similar work flow to create the illusion of a non-rectangular detail in Rhino 8 and earlier.(Non-rectangular details are now supported in Rhino 9 WIP)

You can use this method on the model geometry, as well as on the layout.

  1. Basically, create a solid white hatch on a layer with a white display and print color.
  2. You can prioritize it to be see on the top of the geometry with the DrawOrder commands:
    BringToFront or BringForward
  3. Trim to a boundary curve leaving the hatch to mask the other geometry.

4. Set Print Preview on the viewport
5. Print.

See how it is done here:

Let us know if it works for you.

Sincerely,
Mary Ann Fugier