Hey all! I have been setting up this scene, Modifying textures, adding details etc,. to look more like a certain space Opera.. Back a little ways, I changed something in the lights that screwed up the shadows being cast from the overhead light grid and now I can't get it back to how it was!! There are 3 over head point lights to cast through the grid, but now on the right vertical and angled wall they are clipping into dark bands going across instead of the grid.! I have been trying for hours to fix it but render after render this issue persists.. This is Poser12, Firefly render engine.. BEFORE AFTER Overhead lights SETUP

You might try asking in the Poser 12 forum. I know there have been issues with lighting in Poser 12.

I suppose that it has nothing to do with the lights' attenuation parameter?

The lights are definitely brighter in the After picture. But beyond that, is the issue really the lights or is it the shaders for the wall on the right? In the Before picture, the whole wall on that side seems to have the same material properties. In the After picture, it looks like part of that wall either is now matte black and not showing any illumination, or it's been pushed back out of view. You can no longer see the part that the metal thingy is mounted on, where you could in the Before picture.

Exactly the issue! That wall is a single material, and has not changed from picture one and picture 2.. It's acting like something is blocking the light, but there is nothing between the lights and the wall except for the panel that creates the light 'grid' effect, which has also not changed. The first image, I was happy with the lighting but it just wasn't bright enough... Unfortunately, I made a number of changes at once before re-rendering and it was one of those changes that is causing this effect and I tried to walk it back but I haven't been able to fix it... :(

Extra info on the lights setup... The ceiling of the environment is set to not cast shadows, and I created a second 'roof' just for the cell to create the light 'grid' effect. Since the rest of the ceiling isn't blocking light I Inserted that simple rectangle to light block the cell ceiling lights from spilling into the hallway.

Apologies that I'm just popping in here with an observation before disappearing again and also that I may not have understood the problem correctly!

I notice that the ceiling grid is different in the second image. It has fewer thick bars on it than in the first image and casts fewer thick shadow lines. Has it been shifted or re-sized?

Yes.. I added the angled wall to the left side of the cell, so I resized the grid to fit more evenly in the new space..