OStim has two requirements that are likely to catch new users:
- FNIS (Which builds the animation files for OSA):https://www.nexusmods.com/skyrimspecialedition/mods/3038
- BodySlider (Used for CBBE, UNP, SoS and other body replacers to build presets): https://www.nexusmods.com/skyrimspecialedition/mods/201
Whether you're using Vortex or MO2, the starting point is the same. Go to the Files section of the links above and click to Mod Manager Download. For FNIS, you need the main file only for OStim. Other mods may also require the Creature Pack (Nothing in OSTIM, but some SexLab stuff), and Spells. There's no harm installing them even if they aren't used.Vortex
In Vortex, these are relatively straight forward, one of the things Vortex does right for the user. Once the files have downloaded, Install and Enable them. Go to the Dashboard, and there are buttons for Fores New Idles in Skyrim and BodySlide that should already be present. If they are not, click the Add Tool button and provide the necessary file paths.
FNIS: ..\steamapps\common\Skyrim Special Edition\Data\tools\GenerateFNIS_for_Users\GenerateFNISforUsers.exe
BodySlider: ...\steamapps\common\Skyrim Special Edition\Data\CalienteTools\BodySlide\BodySlide x64.exe
That's it for Vortex. Vortex will automatically run FNIS for you everytime you deploy mods, even if it's unnecessary. That can make deployments slow but takes the work out of your hands. You'll still have to run FNIS once manually, and BodySlide everytime yourself. For FNIS, run it once now. At the bottom is a list of Patches. Select GENDER and SKELETON Arm Fix. FNIS should remember this going forward. Then click Update FNIS Behavior.
When you see something like this, you're done and can close FNIS:
3330 animations for 26 mods successfully included (character).
1 Warning(s).
You're done for now. Vortex will automatically create a "FNIS Data" plugin and handle deploying it for you. It will do this every time you deploy, automatically.
MO2
For MO2, I found things get a little more complicated, and that's why I'm writing this in the first place. Switching from Vortex to MO2, I struggled especially to get BodySlide working. First, once the downloads have completed, install the files as normal. If you got Creatures and Spells for FNIS, click Merge when prompted. Enable both FNIS and BodySlide.
Now, next to the drop down for "Profile" is a little wrench and screwdriver icon. There's two of them, a larger one on the toolbar and a smaller one to the right of Profile. You want the little one next to Profile. Click it and choose Create Empty Mod. Name it FNIS Data, or FNIS Output, whatever you like. Click again and make a second one named BodySlide Output. The new "FNIS Data" mod can be right below the Fores New Idles in Skyrim SE mod. The new "BodySlide Output" mod should be BELOW all of your bodies and mesh files for NPCs, as it may overwrite parts of them.
Now, on the toolbar is a Green and Blue gear icon, click it. Next to the word Executables in the top left corner is a + icon, click it and choose Add from File. You will now need to navigate to the folder where your mods are installed. For me, this is "D:\Modding\Skyrim Special Edition\mods\". Once you're at your mods folder, navigate into "..\Fores New Idles in Skyrim SE - FNIS SE\tools\GenerateFNIS_for_Users\" and choose GenerateFNISforUsers.exe.
This will add a new entry to the list for FNIS named "GenerateFNIS_for_Users". Click it, and if you like, rename it to just "FNIS" or leave it alone. Change the "Start in" to match your mod path again if it does not already, i.e. "D:\Modding\Skyrim Special Edition\mods\Fores New Idles in Skyrim SE - FNIS SE\tools\GenerateFNIS_for_Users". Check mark "Create files in mod instead of overwrite" and select your FNIS Output mod from the drop down. Hit Apply.
Now for BodySlide. Click the + again and choose from file, and navigate to BodySlide's install folder. For me, that is "D:\Modding\Skyrim Special Edition\mods\BodySlide and Outfit Studio\CalienteTools\BodySlide\", and choose BodySlide x64.exe. Set the "Start in" to your game's data path. For me, that is "D:\SteamLibrary\steamapps\common\Skyrim Special Edition\data\".Hit Apply then Ok.
First, click the Executables drop down next to the big "Run" icon on the top right corner. Choose your new FNIS (or GenerateFNIS_for_Users) executable from the list, then click Run. MO2 will tell you it's building the VFS (Virtual File System), then FNIS will open. You MUST launch FNIS through MO2 like this, or it won't see the special VFS or produce the necessary files. At the bottom is a list of Patches. Select GENDER and SKELETON Arm Fix. FNIS should remember this going forward. Then click Update FNIS Behavior.
When you see something like this, you're done and can close FNIS:
3330 animations for 26 mods successfully included (character).
1 Warning(s).
If you find your "FNIS Output" mod and double click it, go to the Filetree tab and you'll see meshes, scripts, and tools folders have been created.
FNIS must be ran every time you add, change or remove animation packs! Unlike Vortex, MO2 will not automatically run it for you. So after you change animation packs, make sure you remember to run it! Sometimes you may need to delete everything in the "FNIS Output" mod to ensure nothing gets left behind.
On to BodySlide! From the executable drop down, find your BodySlide x64 and click Run. BodySlide should find your installed bodies and presets, but it's not ready to run yet! Click "Settings" down at the bottom right corner. Game Data Path should already be filled in, but double check. It should be the path to your actual data folder. For me, that is "D:\SteamLibrary\steamapps\common\Skyrim Special Edition\data\". If you don't do this, BodySlide may not display textures on Preview, even if the bodies do show up.
Click "Advanced" to open two more options. Here we find an Output Path option, which is critical. Change it to the file path for your "BodySlide Output" folder.
For me, that's "D:\Modding\Skyrim Special Edition\mods\BodySlider Builds\". Click OK, and you're ready to use BodySlide.
Oh hey, but how you ask? For both Vortex and MO2 the rest of this is the same. For Vortex, click BodySlide from the Dashboard. If you're in MO2, you're already staring at BodySlide. This is where you can adjust your body files to your personal preferences. Make them skinny, make them thick, big boobs, small boobs, whatever. I have no advice on that, it's personal taste. Most bodies will come with presets ready to go, so to get started, just ignore making new Presets till you're ready and select one. When installing your body, such as CBBE or 3BA (3BBB Body Amazing), you probably chose an initial preset already.
Now, down in the lower left, is a button named Batch Build and a check box "Build Morphs". Check the checkbox, then click Batch Build. The window that opens is where you select what presets to prepare for the game. In 99% of cases, it's fine to select everything. Click Build.
The next screen is where you resolve conflicts. A female body can only use one body, and same for male. Clothing can have one mesh. So you have multiple body files installed, and BodySlide needs to know which one to use. Let's say you installed 3BA. That requires also installing CBBE, so you're going to see "Choose output set #1" and probably about 10 options. You need to pick the one that you want to use here. For 3BA (3BBB), you want to choose "CBBE 3BBB Body Amazing".
As you scroll down you'll have to pick for each conflict. For example, feet and hands will have CBBE and 3BBB listed, so pick 3BBB to match your body.
Continue scrolling down and make selections as you go. The primary selection for clothing will be between simply having your new clothes fit the sliders, or those new clothes also having physics. This is up to your personal preference. I pick Physics in all cases myself. Another example is HIMBO, a Male body. You'll want to pick the version that matches what you installed, for example "SOS - HDT SMP" if you're using HDT SMP physics with SOS. You may have other mods, completely unrelated to OStim and in-game sex animations, that that appear here. For example, KS Hairdos SMP will have options for BHUNP, CBBE and TDB. Pick the one that matches your installed Female body.
Once you've made all Selections, click OK. BodySlide will then build everything needed, usually within 10-20 seconds. The more body mod and clothing options you have the longer it will take. Once it finishes, click OK and close BodySlide.
You're all set.
