I've been carving out 10 floors since the days of sims 2 before they gave us, supposingly unlimited floors, then took it away in sims 3. I remember how they told us with University that we could have therectically 255 floors, but then I found out that sims 2 would crash at 15 floors.
In reality we really don't need that many floors but it would be nice to have at least 10.
In sims 2, I would divide a floor into pieces and CFE raise or lower the pieces in staggard formation to give the illusion that we have more then 10 floors.
My "Correctional SimCenter" was my first lot in sims 3 that attempted to re-use my old tricks. You can check it out here:
http://www.thesims3.com/assetDetail.html?assetId=25802
The latest trick has been improved upon since I needed all 10 floors as a single glass case for my ship.
Quick synopsis:
A 10 floor illusion is created by using a double wall. Each wall holds 5 floors of windows.
By raising the terrain under one set, you can either
- delete the bottom floor and lowering the terrain after raising the wall,
- or lower the terrain and stretching the wall downwards to either create a pillar or leg.
In this picture you can see the two walls. The inner wall is the upper 4 floors and the outter wall is the bottom 5 floors.

I did not like the gap between the two sets of walls, so I reversed the two in my new lot.
Step by Step...
1. create two boxes, one inside the other separated by 1 tile.
2. build 5 floors
3. add floor tiles to the outside of the outside box. These will be used by the flatten terrain tool to raise or lower the wall.

4. hit ctrl-shift-c and type in "constrainfloorelevation off" (known as CFE).
5. now position your raise terrain tool under a corner of the outer box.... and raise ..... till you feel that the outter box is higher then the inner box. You can always re-adjust the height later by repeating steps 5.
6. always work with the first floor. Any adjustment you make to the first floor (raise or lower) will be reflected on all floors.
6. flatten an area with the terrain flatten tool
7. methodically raise the terrain around the box with the flatten tool until the outer box has been raised.

8. after you have raised the outter box, you can now lower the terrain. We will do this a step at a time.
9. lower a section of terrain
10. using the flatten tool raise the box floor back up.
11. repeat steps 9 and 10 for all sides of the box.

12. basically you have created two boxes one inside the other.
13. delete the first floor of the outer box to reveal the inner box. You can leave the corners as pillars, columns, or legs if you want.
14. add windows to the inner box.
15. add windows to the outer box.
16. You are done!!!

To see how well this illusion works, check out this thread
http://forum.thesims3.com/jforum/posts/list/93327.page
As always, feel free to make comments, ask questions or send love and kisses to post office 123 RalphaelNinja Street.
Also check out my lots by clicking on my signature.
Thanks for reading....
Ralphael
Comments
Thank you, Sir Ralph! I'm sure this will come in handy for many people!
You are welcome Ms. Anjubee.... and hopefully handy for you too :P
actually on/off works too for those who plays with lightswitches :P
nooooo bored.... just things to do that I figure that needs my attention :P
I'll give it another try :P
Nice tutorial
thanks TnT_TJ.... well if they had at least carried over (from sims2) the ability to set # of floors, there would be no need for tutorials like this. I remember doing this exact same tutorial for sims2 and it fell by the wayside when university came out :P
There is something SIMiliar without cheat using basements,walls and terraformingtools i used on my castle zureichs tower, but this methode is just great
i guess that the lahmgurkini Autohaus just got a rival in business today
your tutorial did it
good job tutorial..... :P
you are welcome Amoebius
Ty for the Excellent hint..will be trying this..Ty again..
your friend TM1
Well since the rival - Lahmgurkini - had one tower, the ceo of Pursche decided to build more towers 8)
Do you know the new cars from MTS?
nods.... use when needed.... :P and I needed a glass case.... :P