You've spent hours grinding Mystical Crates in Once Human. You finally see that purple or legendary glow, only to realize it’s a duplicate of a weapon you already have or, worse, something you’ll never use. It’s frustrating. But the once human blueprint conversion system is basically the only thing standing between you and a totally wasted season. Honestly, if you aren't using the Blueprint Bureau properly, you're leaving massive amounts of damage on the table.
Most players treat the blueprint screen like a sticker book. They collect things, look at the stars, and move on. That’s a mistake. The conversion system is a specific, somewhat clunky mechanic that lets you sacrifice the "trash" fragments you’ve collected to juice up the guns you actually care about. It’s not just about cleaning up your inventory; it’s about the math of endgame scaling.
How the Blueprint Bureau Actually Works
To even start with once human blueprint conversion, you need the Blueprint Bureau. You build it in your territory. It’s a simple wooden desk, but it’s the heart of your build's progression. When you open it up, you’ll see your owned blueprints and a tab for "Enhancement." This is where the confusion usually starts because the game doesn't do a great job explaining the difference between "upgrading" and "fusing" fragments.
Basically, you have fragments and you have the base blueprint.
Think of it like this: your base blueprint is the recipe. The extra fragments are the seasonings. You can’t make the dish better without more seasoning. When you enter the conversion menu, you’re looking to take those spare fragments—the ones you got from the Wish Machine or crates—and feed them into your primary weapon to increase its Star Level.
A 1-star SOCR Outsider is okay. A 3-star version is a monster. But getting there requires a lot of "XP" in the form of other fragments. This is where the conversion logic kicks in. You can use fragments from the same category to level up your gear. If you’re trying to buff a Sniper Rifle, you’re going to need fragments from other Sniper Rifles. You can’t just dump Pistol XP into a Longbow and expect it to work. It’s a gated system designed to make you specialize.
The Strategy of Sacrificing Purple for Gold
We need to talk about rarity. It’s tempting to keep every legendary fragment you find. You think, "Maybe I'll use that Burn build later." You probably won't. In the current meta, spreading yourself too thin is the fastest way to get stuck on Pro-level Silos.
The once human blueprint conversion process allows you to use lower-tier fragments to supplement the growth of higher-tier ones, but the "conversion rate" is steep. If you’re trying to max out a Legendary (Gold) blueprint, using Blue fragments feels like throwing pebbles at a mountain. You need Purple (Epic) fragments to make real progress.
Here is the kicker: some players don't realize that once you "use" a fragment for enhancement, it’s gone. Permanently. You aren't just slotting it in; you are destroying it to fuel the other.
I’ve seen people accidentally burn fragments for a weapon they were planning to craft next week just because they were clicking too fast in the Bureau menu. Don't be that guy. Take a second. Look at the "XP" value provided by each fragment. Usually, a fragment of the same exact weapon provides the most progress, while fragments from the same family (like Wanderer or Falcon sets) provide a decent secondary amount.
Why Star Rating Is the Real Endgame
Why bother with once human blueprint conversion at all? Why not just craft the gun and be done?
Base damage.
In Once Human, your gear score is tied to your level, but your "Base Attack" is tied to your Blueprint Star Level. If you take a 1-star Last Valor and compare it to a 4-star Last Valor, the difference isn't just a few percentage points. It’s a fundamental shift in how your damage scales with your mods. Since mods usually multiply your base stats, a higher star rating from conversion makes every single mod in your build more effective.
- 1-Star: Standard base damage.
- 2-Star: Slight bump, usually requires a handful of fragments.
- 3-Star: This is the "sweet spot" for most F2P players.
- 4-Star and Above: This is whale or hardcore grinder territory.
Getting to 3 stars via conversion is usually doable within a single season if you’re smart with your Starchrom. If you’re wasting Starchrom on the "Random" crates instead of the targeted blueprint buys, you’re making the conversion process way harder on yourself.
Common Mistakes with the Bureau
One thing that drives me crazy is seeing players ignore their armor blueprints. Everyone wants the shiny gold gun, sure. But once human blueprint conversion works for armor too.
If you’re running a 4-piece Bastille set or the Beret, those fragments can be leveled up to increase your total HP and Damage Reduction. If you find yourself getting one-shot in the Nightmare Prime Wars, it’s probably because your armor blueprints are still sitting at 1-star. You’ve been so focused on the gun conversion that you forgot your shirt needs to be "leveled up" too.
Another thing: the "Wish Machine."
You get fragments from the Wish Machine using Starchrom. Before you spend a single point, look at the "Blueprint Shop" tab (usually G on PC while in the machine menu). You can buy specific fragments there. If you are 20 fragments away from a star-level upgrade, don't gamble on the hammer game. Just buy the fragments directly. It’s a much cleaner way to handle your conversion path.
👉 See also: Why the Ocarina of Time Shadow Temple Still Creeps Us Out Decades Later
The Season Reset Anxiety
A lot of people ask, "What happens to my conversions when the season ends?"
This is a valid fear. Once Human has a seasonal wipe mechanic, but blueprints are one of the few things that are permanent. Your once human blueprint conversion progress carries over. If you spend this season getting your Shrapnel Souvenir build to 3 stars, it stays 3 stars in the next season.
This is exactly why conversion is the most important long-term investment in the game. Your character level resets. Your base resets. Your guns disappear. But the knowledge of how to craft those guns at a high star level remains. It’s the only true "permanent" power progression you have.
When you move to a new scenario—say, moving from Manibus to a Way of Winter scenario—you’ll have to find the materials to craft the gun again, but the blueprint will still have all that XP you fed it.
Actionable Steps for Efficient Conversion
Don't just click things. Follow a workflow.
First, pick one primary weapon and one armor set. That’s it. If you try to convert fragments for three different builds, you will end up with three mediocre builds. Focus all your "same-type" fragments into your main DPS source first.
Second, check your "Blue" fragments. Most people have hundreds of these sitting around. While they don't give much XP individually, in bulk, they can push a 1-star weapon to 2-star without you having to sacrifice your rarer Purple fragments. It’s like using copper coins to pay for a steak—it takes a lot of them, but it works.
Third, pay attention to the "Family" bonus. When you are in the Bureau, look at the icons on the fragments. Using fragments from the same set (like a Huntsman chest piece to upgrade Huntsman boots) gives a synergy bonus to the XP gain.
Finally, save your "Universal Fragments" if you have them. These are rare rewards that can be used on any blueprint. Never, ever use these on a Blue or Purple item. Save them strictly for Legendary blueprints that are hard to farm.
The once human blueprint conversion system is essentially a recycling program for your bad luck. It turns those "trash" pulls from the Wish Machine into the raw power you need to clear the hardest content in the game. Stop hoarding fragments you'll never use. Go to your Bureau, look at your main weapon, and start feeding it. You’ll feel the difference the next time you step into a Silo.
Check your blueprint library now. See how many "unlocked" fragments are just sitting there doing nothing. If you have enough to star up your main weapon, do it before your next boss run. It’s the easiest power spike you’ll ever get.