Zandronum

Im making a kind of portal structure that needs a roof to have the appareance i desire, but for it, i want to make it with 3D Floors so i dont make a lower ceiling and cause that sky view from another sector with a higher ceiling, but i need to give to alter the form of the 3D Floors with slopes, can somebody tell me how to?

Have you considered using a portal? http://zdoom.org/wiki/Stacked_sectors

think you can give me an example wad? im trying to do it, but im doing something wrong cause it doesnt seems to work and the one in the page is down

When you use a portal, the actor for the upper sector needs to be at the same position as the one for the lower sector in the stacked sector.
Secondly, the stacked sector will be viewable by the size of it. You need to make it cover the whole sector where you want to see it.
Lastly, the height of the stacked sector also has to be fully above the lower one, otherwise it won't work either.

Spoiler: example (Open)

It's like putting one sector on top of another. In order to put one sector on top of another, the floor height of the top sector has to be the same as the ceiling height of the bottom sector, otherwise they would either intersect or wouldn't be in contact.

Portal example. Try it with OpenGL since Zan software is bugged with portals (already reported this issue long time ago) : https://www.mediafire.com/?hwbh6u3kfoiesxx

Portals are also buggy in OpenGL. But if you're making one that's just outside, you should be fine.

agaures wrote: Portals are also buggy in OpenGL. But if you're making one that's just outside, you should be fine.

i actually did one that was in an open area, and the floor textures changed to F_SKY, so i'll better leave this trick for later, thanks for the help anyway