Want every newly spawned NPC, vendor, barista or walk-by to be a Sim you actually like? You can do it with MC Command Center’s population settings so the game pulls new Sims directly from your Library instead of random generators. Below is a clean, step-by-step guide based on The Sim Side of Luca’s approach, with a few best-practice extras to keep things running smoothly.

What you’ll need

  • MC Command Center (MCCC) by Deaderpool
    Required modules for this method:
    • MC Command Center (package + ts4script)
    • MC Population (package + ts4script)
    • MC Tuner (package + ts4script) – needed to respect appearance rules

Optional: MC Woohoo, MC Dresser etc. are not required for NPC-from-Library spawning.

1) Download and install MCCC the right way

  1. Google “MC Command Center Sims 4” and open Deaderpool’s official site.
  2. Go to Downloads. Grab the latest version that matches your game patch.
  3. Extract the .zip. Inside you will see many modules. Keep only:
    • MC Command Center (both files)
    • MC Population (both files)
    • MC Tuner (both files)
  4. Place those six files inside Documents\Electronic Arts\The Sims 4\Mods\MC Command Center
    • Keep script files no deeper than one folder level under Mods.
    • Make sure Resource.cfg is present in Mods (it is by default).
  5. Launch the game, go to Game Options > Other, enable “Enable Custom Content and Mods” and “Script Mods Allowed”, then restart once.

2) (Optional) Start from a fresh world for clean results

You can use any save, but the cleanest outcome comes from a blank save such as Seriously Blank Save by SeriouslySims. It removes preplaced Sims and lots so the population is built entirely from your Library.

If you do not want a blank save, at least purge unwanted premade or randomly spawned households:

  • Manage Households > Other Households
  • Delete NPC households you do not want in your world.
  • Keep any of your own families you want to remain active.
  • You can skip this if you are happy with the current mix.

3) Tell MCCC to use your Library Sims for every new spawn

  1. In Live mode, click any computer > MC Command Center > MC Population > Population Settings.
  2. Set the following:
  • Import Tray Sims Percent: 100
    (The default is 0. Set to 100 so all new NPCs are generated from your Library.)
  • Import Tray Sim Type:
    • Only My Sims – if you only want Sims you created
    • Any Saved Sims – to include Sims you downloaded and saved to your Library
  • Limit by Tags (optional):
    Use include/exclude tags if you want to curate who can be used.
    • Example: tag your preferred Library Sims with MCCC_include in their description, then set the include tag here.
  • Include Gender Options: Enabled
    Ensures spawned Sims keep the original gender settings you set in CAS.
  • Include Clothing: Enabled
    Prevents the game from swapping outfits you made in CAS.
  • Import Sim Name: Skip Sim If Name Exists
    Prevents duplicate clones of existing Sims with the same name.
  • Import Bypass Appearance: Enabled
    Blocks the game from changing the face or outfit of imported Sims.

Click Back to exit the menu and let the world run. New NPCs that the game spawns should now come from your Library with your looks and outfits intact.

4) Build a healthy “feeder” Library so spawning never breaks

This step is the secret to smooth results. MCCC can only spawn from what you provide. To prevent age or role mismatches, stock your Library with plenty of Sims across:

  • Ages: elders, adults, young adults, teens, children
  • Genders and body types
  • Occult types (if you want them in your world)
  • Outfits for everyday, career, hot/cold weather etc.
  • Vendor/staff-ready Sims: add role-friendly looks for baristas, bartenders, vendors, lifeguards, nannies, spa attendants, etc.

Tip: Search the Gallery for “NPC”, “nanny”, “vendor”, “bartender”, “spa” and save those households to your Library. Tweak them to your style in CAS full edit (use testingcheats on then cas.fulleditmode) and save.

Why this matters:
If the world needs elders but your Library has none, the game can up-age your adult or teen Library Sims into elders to fill quotas. The fix is simply to add more elders to your Library.

5) Quick tidy tips to avoid confusion

  • Tagging workflow:
    In the Library description, type a tag like MCCC_include for any Sim you want eligible. Then set Limit by Tags in MCCC to include only that tag if you want fully curated spawning.
  • No duplicate clones:
    The Skip Sim If Name Exists setting prevents duplicates of an existing household.
  • Script depth:
    Script files can only be one folder deep. Example:
    Mods\MC Command Center\mc_cmd_center.ts4script – OK
    Mods\MyMods\MCCC\mc_cmd_center.ts4script – too deep, will not load

6) Results to expect in game

  • New vendors, service Sims and walk-bys will be pulled from your Library.
  • Your faces, outfits and gender settings are respected.
  • Neighborhoods will slowly fill with your style of Sims instead of random generators.

If you still notice a stray random Sim, give it time. As the game spawns more roles, MCCC will keep selecting from your Library.

Troubleshooting

I see teens turning into elders.

  • You likely do not have enough elders in your Library. Add several elder Sims and continue play.

The game changed someone’s outfit.

  • Double-check Include Clothing is enabled.
  • Ensure MC Tuner is installed.
  • If you use outfit-override mods, confirm they are updated.

Some NPCs are still default-looking.

  • Confirm Import Tray Sims Percent is 100.
  • Make sure the Sim type is Only My Sims or Any Saved Sims as intended.
  • Add more Library variety. The game cannot pick what you do not provide.

Settings aren’t saving.

  • Exit the MCCC menu with Back rather than ESC.
  • Save your game and reload.

Optional helpers

  • Seriously Blank Save – start with a truly empty world to fully curate who appears.
  • Gallery playlists – make a “NPC Feeder” folder and regularly add fresh vendors, elders, and teens.
  • Pose/thumbnail CC not needed – MCCC pulls the Sim, not their CAS poses.

Final checklist

  • Installed MC Command Center, MC Population, MC Tuner correctly
  • Enabled mods and script mods in Game Options
  • Set Import Tray Sims Percent = 100
  • Set Import Tray Sim Type as desired
  • Enabled Include Gender Options and Include Clothing
  • Set Skip Sim If Name Exists
  • Enabled Import Bypass Appearance
  • Stocked Library with many Sims across ages and roles

Source: https://www.youtube.com/watch?v=fn4n88WWQ0g&ab_channel=TheSimSideofLuca

FAQ: Using MC Command Center to Stop Ugly NPCs in The Sims 4

Q: What is MC Command Center (MCCC)?
A: It’s a powerful mod by Deaderpool that lets you control population, pregnancies, careers, cheats, and more. For this method, you only need three modules: MC Command Center, MC Population, and MC Tuner.

Q: Where do I download MCCC?
A: From Deaderpool’s official website. Always grab the latest version that matches your Sims 4 Patch.

Q: Which MCCC modules do I need to keep?
A:

  • MC Command Center (package + ts4script)
  • MC Population (package + ts4script)
  • MC Tuner (package + ts4script)

Delete the rest if you’re only using it for NPC spawning.

Q: Where do I put the files?
A: Place them in Documents > Electronic Arts > The Sims 4 > Mods > MC Command Center. Keep scripts only one folder deep.

Q: How do I tell the game to only spawn my Sims?
A: In game, click a computer → MC Command Center → MC Population → Population Settings. Then:

  • Set Import Tray Sims Percent to 100
  • Set Import Tray Sim Type to Only My Sims or Any Saved Sims
  • Enable Include Gender Options
  • Enable Include Clothing
  • Set Import Sim Name to Skip Sim If Name Exists
  • Enable Import Bypass Appearance

Q: Do I need a blank save?
A: Not required, but a blank save (like Seriously Blank Save) helps if you want only your Library Sims to populate the world.

Q: What happens if I don’t have enough Sims in my Library?
A: The game may change ages or recycle Sims (e.g., turn teens into elders) to fill missing roles. Always stock your Library with plenty of Sims across all ages.

Q: How do I prepare my Library?
A: Save Sims of all types: elders, adults, teens, children, NPC roles (vendors, baristas, lifeguards, etc.). You can download premade NPCs from the Gallery and edit them.

Q: Can I filter which Sims show up?
A: Yes. Use tags in Library descriptions (like MCCC_include). In MC Population settings, enable tag filtering to include or exclude Sims.

Q: Will the game change my Sims’ clothes or faces?
A: No—if Include Clothing and Import Bypass Appearance are enabled, your Sims spawn as you made them.

Q: What if I still see random NPCs?
A: Double-check your settings, add more Sims to your Library, and let the world generate new roles over time. Random Sims should disappear as your Library fills the population.