Hi I have EADM/Disk and Origin versions of all expansions and The Sims 3 and my wife has Steam version . (She is only missing one DLC)

The Sims 3: Katy Perry’s Sweet Treats
https://steamdb.info/app/223591/info/

So she didn't want to bother with Origin and Origin DRM . Steam way to go for her , I don't want to bother with disks too Origin is for me . Luckily retail keys are working on Origin

And I tried to copy this DLC for her but here are the facts :

Steam version is 1.67 , Origin version is 1.69 .
With that they made some cleanups in files and some cosmetic changes in launcher .
Steam version have /Game/Bin folder under each expansion and stuff files . But now Origin missing those files . EADM/Disk version has same files too but they are different than Steam ones .
Without that folder , expansion seems working under Steam but on Launcher version number seems as 0.0.0.0 .

After I checked all those files I made a conclusion :

TS3SPXX.exe , TS3EPXX.exe , skuversion.txt , Sims3Launcher.exe , Sims3SPXXGDF.dll , Sims3EPXXGDF.dll , GraphicsRules.sgr in each expansion's Game\Bin folder are completely obsolete .
Even Default.ini is unnecessary but it's used by Launcher .

Notes :

I am not speaking about the files under base game folder . Those are still present in 1.67 Steam or 1.67 EADM/Disk version .
Those are only my knowledge . So that's why I decided to ask this on a tech heavy The Sims website . Please help to me . Am I right now ?
Or those files are critical for something ? Also if someone has Steam version of this DLC , could post their Default.ini ?

As you have noticed, the Steam version and the Origin version are different. I know of no legal way to put an EP or SP from Origin into the Steam version.

If you have registry entries it's quite easy job . How there is no way ? What do you mean with legal also if you already have license of the game ?

Steam is not set up to accept a non-Steam version. (Although it does allow you to run games, and they politely give the product code if you buy the Steam version so that you can play with Origin, since Origin (EA) owns the game. But EA simply allows Steam to sell their own version of the game, probably with a healthy kickback to EA for the licensing rights. Despite both being Sims 3, they are two different games.

There are a number of places where this is discussed, but the most recent that I was able to remember about is here: http://www.modthesims.info/showthread.php?t=587296

The Steam base game and Orgin/Disc base game, even if both at 1.67, have different internal build numbers. That is why core mods in particular need to take each version into account or the player gets a nasty core version mismatch warning upon startup. They cannot be mixed and matched.

They are technically not the same games even though they play the same. I assume this is true of the EP/SPs for each platform as well.

Guys , do you know something like MD5 hashes ? It's industry standard . I am speaking with that . Except base game , EP/SP files %99.9 same for all versions . If you don't believe check for yourself . I am not speaking without proofs .

I'll accept that essentially the only real difference between the two are the build numbers if even that for a pack rather than the base game. Although the base game differences might be enough to be such that the packs just won't work on the other platform.

But let me put this another way, although it really isn't any different from what Ghost was saying. Hacking the game or pack files so that Steam accepts an Origin version of the game (or vice versa) as one of its own would be illegal in the sense that it would be a violation of the EULA. You're gonna go to jail for a very long time so as not to be such an obvious and open threat to society. Someone has to think of the children, blah blah etc.

Okay no, just kidding on that last part. But I don't think this is the sort of thing one can get assistance with here, if it's even feasible.

Seems I forget to ask , game already working flawlessly I am asking info about files I wrote . They are doesn't seems functional to me .