How many free rigged characters fit the UE5 Manny skeleton?
We read the skeletons of 445 free rigged humanoid characters under CC0, CC-BY or MIT licences and checked each one against the Unreal Engine 5 Manny skeleton (SK_Mannequin, 89 bones). The files were read on 4 November 2026; only counts are published, never the models.
The numbers
- 0 of 4450 of the 445 free rigged characters we read play UE5 Manny animations as they are, with no rename and no retarget.
- 99%99% (442) have every body bone a retarget needs under other names: they need a rename or a name map but no new weights, and 71% of them also need a root bone added.
- 1%1% (3) need a re-rig because body bones are missing, such as the hands or the forearms.
- 0%0% have any twist bone, while Manny has 16 of them to keep wrists, elbows and knees from collapsing.
- 2%2% (10) have a bone named root above the pelvis, the bone Unreal uses for root motion.
- 43%43% (191) would arrive in Unreal under 50 cm tall at the file's own unit, a scale fix to make before any animation looks right.
Charts
What each character needs before Manny animations play
445 characters. "Rename only" means every required body bone is there under another name; 312 of them also need a root bone added.
Bone naming schemes
How the bones are named. Only "Unreal (Manny names)" matches SK_Mannequin by name.
Finger bones
Fingers with at least one bone, on each hand. Manny has all five on both hands.
What sits above the pelvis
Manny's pelvis hangs under a bone named root, which carries root motion.
Rest pose
Manny rests in an A pose at about 55 degrees. A T pose character gets the arm angle difference in every frame unless the retarget corrects it.
Height at import
Manny is 179 cm. Stylised characters are often taller or shorter on purpose; a character under 50 cm or over 10 m usually means a unit mismatch.
- 61% (272) have finger bones for all five fingers on both hands; Manny animates 15 finger bones per hand.
- 294 characters rest in a T pose and 147 in an A pose like Manny.
- 218 characters (49%) stand between 120 and 220 cm, close to Manny's 179 cm.
- The median skeleton has 65 bones; Manny has 89.
- 312 of the 442 rename-only characters have no bone above the pelvis (or none we could place), so a root bone has to be added as well.
- 117 characters carry a VRM humanoid bone map, which VRM plugins for Unreal can read instead of the names.
- 445 characters were saved Y up and 0 Z up. Unreal's importers convert both, so the up axis did not decide any result.
By source
| Source | Licence | Files | Characters | As it is | Rename only | Re-rig |
|---|---|---|---|---|---|---|
| Microsoft Rocketbox | MIT | 115 | 115 | 0 | 115 | 0 |
| KayKit | CC0 | 9 | 9 | 0 | 9 | 0 |
| Khronos glTF samples | CC-BY-4.0 | 2 | 2 | 0 | 2 | 0 |
| three.js examples | CC0 | 1 | 1 | 0 | 0 | 1 |
| 100Avatars | CC0 | 300 | 299 | 0 | 299 | 0 |
| Open Source Avatars community | CC0 | 18 | 17 | 0 | 17 | 0 |
| Kenney | CC0 | 2 | 2 | 0 | 0 | 2 |
Method
- We listed 593 files from the sources above: each repository's file list and the registry's JSON, one request each, with a pause of at least one second between downloads. Files were downloaded one batch at a time, read, and deleted; no model was kept or shared.
- Blender 5.0.1 read every file headless with its own FBX and glTF importers (a VRM file is glTF with extra data). For each file we recorded the bone names and parents, each bone's rest position, the skinned meshes, the mesh bounds, and for FBX the file's own up axis and unit.
- The bone names went through the same matching code as the skeleton checker on this site: Manny names, Mixamo names, and a best guess for other conventions (Biped, VRoid, Rigify and own names). For 3ds Max Biped fingers, which carry numbers instead of finger names, we added one map (Finger0 is the thumb, Finger1 the index, and so on).
- Every skeleton the name match sent to re-rig was then looked at by hand. 5 characters had every body bone in the right order under names no automatic map knows (joint numbers, or a typo such as RightUpLeg1); they count as rename only, with the names matched by hand.
- Colour variants of one character (same source, same skeleton, same vertex count and the same height) count once: 447 rigged files became 445 characters on 106 distinct skeletons.
- Plays as it is: Manny's bone names and hierarchy, with a bone named root on top. A file that passes can use SK_Mannequin itself, so Manny animations need no retarget.
- Rename only: each of the 15 bones VRM 1.0 requires for a humanoid (hips, spine, head, and both upper arms, forearms, hands, thighs, shins and feet) is found under another name, in the right parent order. No weight has to be painted; a root bone may have to be added above the pelvis (counted below), and the IK Retargeter, or a rename, does the rest.
- Re-rig: a required body bone is missing, the bones are in another order, or no mesh is skinned to them.
- Rest pose: the angle of the upper arm below horizontal at rest. Under 20 degrees is a T pose, 20 to 70 degrees an A pose. Manny itself, measured the same way, rests in an A pose at about 55 degrees and stands 179 cm tall.
- Height: the skinned mesh from lowest to highest point, after the importer applied the file's unit. Hair, hats and weapons count.
Sources, licences and access terms
- Microsoft Rocketbox: MIT (LICENSE.md in the repository). github.com/microsoft/Microsoft-Rocketbox. Each avatar's main FBX, downloaded from the public repository. GitHub's Acceptable Use Policies allow research use of public information: "Researchers may use public, non-personal information from the Service for research purposes, only if any publications resulting from that research are open access." This page is open access.
- 100Avatars (R1 to R3, Polygonal Mind): CC0 in the Open Source Avatars registry; the older GitHub repository states CC-BY 4.0. opensourceavatars.com registry (github.com/ToxSam/open-source-avatars), files on Arweave. The registry publishes its JSON for programs and says model URLs "should not require proxying or caching". We took the FBX where the registry offers one (R1 and R2) and the VRM otherwise (R3).
- Open Source Avatars community collections: CC0 (per collection in the registry's projects.json). NeonGlitch86, ToxSam, Halloween Rising and Xmas Chibis, files on IPFS gateways and GitHub. The same registry and the same rules. The two largest collections (Grifters Squaddies and VIPE Heroes) were left out to keep the download small. All of Halloween Rising and Xmas Chibis, and a few others, sit on the dweb.link gateway, which answered "429 Too Many Requests" with "Retry-After: 900" and a Sunset date of 21 September 2026. We did not retry or use another gateway, since the registry asks programs not to rewrite its URLs, so those files are counted as not downloaded.
- KayKit character packs (Kay Lousberg): CC0 (LICENSE.txt in each repository). github.com/KayKit-Game-Assets: Adventurers 1.0 and Skeletons 1.0. The FBX characters from the public repositories, under the same GitHub policy as Rocketbox.
- Kenney (Mini Characters, Blocky Characters): CC0 (License.txt in each pack). copies already on our test machine. kenney.nl's robots.txt disallows /downloads/ for every crawler, so nothing was downloaded for this study; we read four files we already had.
- Khronos glTF samples and three.js examples: CC-BY 4.0 (CesiumMan, RiggedFigure); CC0 (RobotExpressive). github.com/KhronosGroup/glTF-Sample-Assets, github.com/mrdoob/three.js. Each model's own licence file. BrainStem was left out: its licence is a Poser EULA, not an open licence.
Sources we did not use
- OpenGameArt: Its robots.txt says "Disallow: /" to Claude-User and Claude-Code, the agents we used, so we did not read it.
- itch.io packs: Its robots.txt disallows /game/download/ for every crawler.
- Quaternius: Since 28 August 2026 new downloads come under the Quaternius Asset License (QAL v1.0): free to use, but not CC0, CC-BY or MIT, so outside this sample.
- Sketchfab and Mixamo: Downloads need an account. We used public files only.
Limits
- Names and hierarchy only. We did not compare bone orientations, rolls or skin weights. Two skeletons with the same names can still point their bones differently, and then a Manny animation looks wrong until it goes through the IK Retargeter. "Rename only" means no new weights and at most a root bone added, not zero work.
- The sample leans on two large libraries: Rocketbox and 100Avatars make up 414 of the 445 characters (93%), and each builds its characters on one family of skeletons. The table by source shows each library on its own.
- Blender read the files, not Unreal. Unreal's FBX importer can treat a few nodes differently (for example, it keeps an FBX skeleton root such as Biped's Bip01 as a bone, which we counted as a bone above the pelvis).
- Free and openly licensed only. Paid packs and marketplace characters may look very different, and so may characters made for Unreal on purpose.
- Some files could not be downloaded or read (144) and some had no skeleton (2); they are left out of every percentage.
Data and citing
The aggregate CSV holds every count on this page, by section and by source. It names no file and no character, and no model is shared. You may quote the numbers and use the CSV with a link to this page.
Cite as: Cosindra, "How many free rigged characters fit the UE5 Manny skeleton?", 4 November 2026, https://cosindra.ai/research/rigged-characters-vs-ue5-manny
Check your own character
The free UE5 Skeleton Checker runs the same name and hierarchy check on your own file in the browser, without an upload. If a character needs a re-rig, RigMaster, one of the Cosindra workspaces, rigs a mesh to the Manny skeleton.