Le sigh. So I went back to test Ghostship's wonderful materials and lights by setting up the background node the way he explains in his tutorial.

I did the setup, exited the material room, it looked great. Then I entered the mat room again to adjust a setting on my model's eye texture. Surprise! When I moved back to the Pose Room the background node I set up was disconnected and the original default setup was auto-plugged in back.

This is very bizarre. I retested twice. This happened after a Windows 10 update so no idea what got messed up. Will file a bug report regardless. Just wanted to see if anyone manages to replicate.

Did you delete the "extra" node that the background loads with by default? The background works fine if I leave them. It reverts when I remove them. By extra nodes, I mean BC Color, Black, BG Environment, BG Picture, and BG Movie.

And today's fun fact, the ground plane shadow catcher works well if you're using the background rather than a sphere.

I will try leaving them, thanks for the suggestion. It's still a bug, because why should it reconnect something I explicitly told it to change? That background node is buggier than an ant hive, it had several since 12 was released.

I confirm this automatism: the background's defaults nodes must be present, even if they are not used, and it's also in Poser 11. Example in Poser 12 (same effect in Poser 11)

You don't even need to get out of the Material room: select another object, and then come back to the background node.

I'm in full agreement with Y-Phil and RedPhantom. Those nodes are fully entrenched in the Background nodes setup, like a bad tune, they keep coming back.

Yeah. Not sure I'm happy about this. Bug report was filed, I pointed John to this thread to see I'm not nuts and others also experienced it.

This is nothing new. It was in poser 7. If I had to guess, it has something with being able to set a background color in the pose room. I like to have my background set to green for higher contrast. Even when I set up a background image, the background stays green in the pose room.

I literally never had it change back to the original. The issue is that it removes the HDRI I set up for lighting. That is not something I experienced before.

The design probably wants those nodes there because otherwise there might not be any convenient way to restore them if you wanted them. But if that's the case, it shouldn't be possible to delete them at all. Certainly it shouldn't mess up the nodes you've left.

yes, you need to leave those node there. I have them in my own preset so there isn't any funny business when I load it up.

Grr. And of course, this is nowhere in the manuals so people will be taken by surprise. Appreciate the confirmation.

I don't think I've ever tried removing them. I usually just unplugged whichever one was plugged in, minimized them size-wise, and moved them out of the way.