The twisted floating gray things are a membrane structure, it looks like that because I did a cut plane.
The problem appeared when I wanted to change the sky setting from one hdri sky to another hdri sky. The render was working well before it but just after I change it suddenly the green sky appeared. Now I put no matter what sky setting the previsialitation shows that green solid color, just if I disable the sky visibility it desappers.
But this project have a context. I was working normaly with it in a previous file when I render it and it was just all black. Then I see a video in youtube that told me that probably the problem was some incompatibility with SKP migrated objects from sketch up that i was working with. So I deleted some of the more heavy objects and render again and then the solid black in all the screen didnt show up but just in some objects. So I thought i would be a good idea just copying all the elements and pasting them into another file. After that, in the render the black objects didnt appear but the physical sky was too dark, so I changed it to the hdri sky but it neither was good enough and changed to another and then it all broke (green sky).
