Spawning portals as props -- or at least just material?

Hi. There are many posing opportunities that I can use the portals for. Portal gun mods don’t work too well and look ugly, so I thought I just use the solid-colored one with the nice swirly effect. But when I spawned it it was an effect with the purple checkerboard square, so I couldn’t use that. Then I tried to spawn a construction prop (there’s a circle, which is close enough if I use perception tricks) to see if I could apply it with materials and colors but it didn’t work right and looked very strange.

Has anybody any suggestions on how to do this? I did find a thread here and the last post semi-explains, but the RT camera doesn’t work anymore (at least not without an addon) and half the post looks like it got cut off or something.

Thank you.