This tutorial is currently a work in progress. I am working on the images for the part on peaked ceilings but will be adding them soon. I'd appreciate any feedback and if anybody would like to test that'd be awesome!




Aim of this Tutorial:
To show you how to slope the sides of your ceiling leaving a flat bit in the centre. If you’re feeling adventurous you can also try doing the peaked ceiling.
Difficulty:
Beginner-intermediate. As long as you’ve built a couple of buildings on TS3 before you should be able to follow this quite easily. The peaked ceiling is slightly more complicated but still do-able for most builders.
Credits:
Thanks to Armiel for testing my first attempt at this tutorial and convincing me to make it less wordy and complicated. Armiel also taught me the ‘Precise Terrain Elevation’ technique and allowed me to use it in this tutorial.
Thanks to Tom (TVRdesigns) for proof reading and unwittingly starting a chain reaction that led to me writing this (I was copying a style of CFE’d roof he’d shown me when I first discovered sloped ceilings were possible).
Also thanks to Ben and Jaguwar for proof reading my first draft


Set-up
> Working with a level base build your home as normal.
> Add your interior walls to the top floor now as it will be a lot more difficult to change them later.
> Off to one of the sides that you plan to have the gable end, build a guide wall. The guide walls need to have the same amount of levels as your house. (ie my basic home has two levels so my guide wall is two walls high).
> Open the cheats panel (ctrl, shift + c) and type in constrainfloorelevation false


Placing the Roof
I want my vaulted ceiling to start sloping up from half wall height so that’s the point I need to place my roof. To do that you need to sink your guide wall so that the top of it reaches half wall height on the equivalent level of your house:

> From ground level lay 8-steps and level out your guide wall [a]. (Doing them in two halves will save a little time later).
> With the level tool grab the newly created lowest point of your guide wall and drag it across the top of your house [b ]. Your walls should all be half height now so go ahead and add your roof [c+d].


Sloping the Ceiling
We already have the base of the slope so we might as well work our way up (if you’re doing a peaked ceiling, however, it’s better to start from the top and work your way down after you’ve placed the roof).

> With your level tool level the guide wall to 4-steps below ground level [e] then drag the level tool from the new highest point of the guide wall across your house. Be careful to leave the edges at the half wall height [f].
> Level the guide wall out to normal ground level [g] and once again, drag the level tool from the newly created highest point of the guide wall across the centre of your roof. Be careful to leave one tile between your sloped tile and the tiles you’re levelling [h].


Alternative Method: Peaked Ceiling

See this post for a rough and ready guide

Final Touches
> The main body of your ceiling has sloped edges now [i] but you’ll need to fix any dormers you have. Just drag the level tool from the highest point to the centre of your dormer. Leave one tile either side of the dormer to allow for the slope [j]. Once you are done you can open the cheats panel and type constrainfloorelevation true
> Occasionally you will get some clipping [k], you just have to adjust the roof height of the dormer to compensate.
> The final step is to get down low so that you can see the flat ceiling tiles in the centre of the room/dormer. Grab any floor tile and touch it to the ceiling [l]. You don’t have to place the tile, the ceiling slopes will automatically appear.




Examples



Peaked Ceiling: