(this is happening to me with all sorts of mods)

I get confused with the files. I need to place the data in "C:\Program Files\EA GAMES\The Sims 2\TSData\Res\Catalog\Scripts" but the Ultimate Collection doesn't have TSData as an option, only the expansions. Which expansion TSData file do I need to put this in for it to work?

(really sorry if this is seriously dumb)

(I do not think it's dumb question)
I haven't installed UC, but there should be a collection that includes base game, like Double Deluxe or something. If you can't find that, try installing custom scripts under
(your UC install folder)\TSData\Res\Catalog\Scripts
(default install folder: \Origin Games\The Sims 2 Ultimate Collection\Fun with Pets\SP9\)

So "C:\Program Files (x86)\Origin Games\The Sims 2 Ultimate Collection\Fun with Pets\SP9\TSData\Res\Catalog\Scripts" is the folder I definitely want it in, correct?

If you can find Double Deluxe directory, try to put script under Double Deluxe\Base\.... first and check if it works.

Okie doke.

It's a little late, so I'll try it tomorrow and see what happens haha.

Moved to help.

The Scriptorium by Numenor works with UC so you could use that to install scripts. It will create links in your Downloads folder to C:\Program Files (x86)\Origin Games\The Sims 2 Ultimate Collection\Double Deluxe\Base\TSData\Res\Catalog\Scripts

Tried putting it into DD & FWP and so far I'm not having any luck.
I also have no idea how to use the Scriptorium.

I gave up - I've done everything, from installing the Scriptorum (which installs, appears, shortcuts and all, but no stairs) - from removing the intaller and tried to put txt. files into first Pets (proper place) as advised by the FAQ and then removing them again and inserting it into the proper place in Double Deluxe - nothing. I gave up. I will simply build houses without stairs and only use other lots with stairs.

You have to do three things to get modular stairs to appear. When you download modular stairs, they should come with two files: a package file and a txt file. This is what you do.

1. Put the package file in your Downloads folder.

2. Install Scriptorium

3. Go to your Downloads folder. See the shortcuts for Scriptorium. Get the txt file (wherever you put it when you downloaded and unzipped the stairs). Drag the txt file into the Scriptorium shortcut for modular stairs. Scriptorium modifies the game script files for you. You have to put the new text in there though for it to add to the game script files. It sounds like you did steps one and two but not three.

If you don't do all of these things, the stairs won't show up. Number three is usually the most confusing. I manually added the txt files for years because I didn't understand how to do it. If you've done all three things and the stairs don't show up, it's still probably because the txt file hasn't been added or it's in the wrong place, but I'm afraid I'm out of ideas how to help with that with UC.

I have done all that. I have also done it before UC It does not work in my game - I am not new to the scriptorum. It does not work in my game. I tend to think it might be one of the things that will work on some computers and not on others.

I am having the same problem with installing modular stairs with Scriptorium and the UC. I am trying to install HughLunatic's open underneath stairs that are slaved to her recolorable stairs. When I open the Scriptorium modular stairs folder I see the 'put here the custom scripts for modular stairs' file followed by all the individual text files for the stairs I have tried to install. Is this what I am supposed to see, or were those text files supposed to merge in somehow with the first file? Is there something I can do manually to make them work?
FWIW, I am also having the same problem with custom fireplaces. I haven't tried the other three scriptorium options.

That's what you should see.

What's the file path of the folder with the "put custom scripts here" file in it? And what's the file path of your Downloads folder?

My filepath: origin games - The Sims 2 UC - Double Deluxe - Base - TSData - Res - Catalog - Scripts - Scriptorium - Modular Stairs. ( have tried to move it to Pets Collection - it then does not show up at all in my downloads folder. (Neither does any stairs). Bypassing the scriptorium (I actually uninstalled it and try to use only the .txt files - also had no sucess at all. Installed Scriptorium again, exactly the same - no stairs).

This is the only thing that does not work in my game. In fact, my game runs exceptionally well these days - much better than it had done with the CD's. The SCPI now works fine since it was updated; all my downloads are perfect. It is only these stairs - and at this stage I am getting by without them. However, I would like to get it to work too

Manual Method:
Go to Computer/LocalDisk/ProgramFiles(x86)/OriginGames/TS2UC/DoubleDeluxe/Base/TSData/Res/Catalog/Scripts. There should be about a dozen .txt files in it. The one you want is modularstairs.txt. MAKE A backup COPY! Open the original with notepad. DO NOT USE MICROSOFT WORD FOR THIS! DO NOT! DO NOT! DO NOT! (Have I made myself clear people?!!! )

Open the .txt file for the modular stairs you want to add also with notepad. Copy the ENTIRE text from the stairs you want to add and paste it into the ORIGINAL modularstairs.txt
I usually prefer to place them in numerical order, but this isn't really necessary. Save the changed file (overwrite the original). You should now be able to use you new modular stairs.

I also highly recommend making a backup copy of the changed modularstairs.txt, because if you patch the game at any point, it will be over written by the patch with the original file. Actually, as far as I can tell, changing any of the original scripts or nlo files automagically makes Origin want to "patch" the game, so ignore it letting you know a patch is available.

Are you placing the script file in C:\Program Files (x86)\Origin Games\The Sims 2 Ultimate Collection\Double Deluxe\Base\TSData\Res\Catalog\Scripts\Scriptorium_ModularStairs as well as placing the actual .package file in C:\Users\<user>\Documents\EA Games\The Sims 2 Ultimate Collection\Downloads?

Scriptorium installation works with UC, as does custom stairs.

I do - I've used it without any problems before the UC. It really does not work in my game. I don't know why. As I said, all my other downloads work perfectly, and my game actually runs like a dream.

I tried this - same non-result. However, this Origin patch thing might have been the problem here, I had to repair my game a couple of times due to having had to make some small hardware changes (graphic card had a loose connection) - yet, it was after the last repair on Origin that I install the scriptorium again. Tell me, should I then uninstall the Scirptorium in order to use this method?

My path for the scriptorium stair files is: C:\Program Files (x86)\Origin Games\The Sims 2 Ultimate Collection\Double Deluxe\Base\TSData\Res\Catalog\Scripts\Scriptorium_ModularStairs
For the fireplaces it is: C:\Program Files (x86)\Origin Games\The Sims 2 Ultimate Collection\Double Deluxe\Base\TSData\Res\Catalog\Scripts\Scriptorium_Fireplaces

My path for the download files is: C:\Users\MyName\Documents\EA Games\The Sims™ 2 Ultimate Collection\Downloads\Build\HughLunatic

All other mods and custom content seem to be working correctly except for MogHughson's desk locators which seem to make sims think there are no desks when placed. I run a pretty heavily modded game, so there might be one or two other issues I haven't noticed, but all the big things like ACR are working, so it's not something as simple as "Turn custom content on, Sunbee!" unfortunately.

The only difference between @Sunbee and me is probbably that I have less mods, but I do have ACR, which works perfectly too, and everything cc works well. I've been using Kativip's open stairs because they don't have a .txt file.

Nope, this is just doing by hand what the scriptorium does for you., although I think the scriptorium just adds the newest stair to the end of the list, which is usually out of numerical order. This makes my OCD go batshit crazy; so, since I have to eventually clean things up manually anyway, I just usually do it myself, which is why I know the process.

Thank you, I am going to try it again - I think it might be the Origin update overriding files, because that certainly did not occur to me

Wanted to add, just tried it myself, with sims 2 ultimate collection. Worked fine. I even did redundant stuff like first placing the text in a kazillion script files where I thought it might go, since the ultimate collection thoroughly confuses me, then found out about the scriptorium, and did it too, and it all worked fine! Wanted to add, there is just an extra step into a world (or something like that) stair symbol in the build mode for HugeLunatics shinto stairs, open underneath, and the other tan step into a world stair symbol is the default override of the original stairs, (also HugeLunatic's but you need THAT one or the open underneath ones don't work, as the open underneath are a slave mesh to her default override. Perhaps that is part of the problem for some of you?) so neither one shows a custom content asterisk.