Custom Character Meshes#

This guide walks you through the process of packaging custom character mesh assets for the Creator Hub using the Creator Kit.

1. Acquiring Your Custom Character Mesh Asset#

Either use your favorite modeling tool to create and skin a custom character mesh, or get a character mesh from Fab.

Source Assets

If required, you can download our HELIX Unreal Engine 5 Manny and Quinn base skeletal mesh source files to use as reference on your character work.

Warning

Custom character meshes do not support wearables, and they will be disabled in character customization game UI if a custom character mesh is chosen.

Warning

Custom character meshes should closely match the proportions of the standard Unreal Engine 5 Manny/Quinn mannequins. This is not a strict requirement; however, substantial differences in limb length, body proportions, or overall scale may cause animation or gameplay systems to behave incorrectly, including interaction traces, first person view mode quality, collision/hit detection, IK solvers, and ability logic.

2. Preparing Your Custom Character Mesh Package#

For this tutorial, we will be using a robot character mesh acquired from Fab.

Launch the Creator Kit editor.
Access the HELIX Packaging Tool from the main toolbar.
In the packaging tool window, click New Package.
Enter a unique Package Name (e.g., MyCustomCharacterMesh).
Select Wearable as the Package Type. The workflow with custom character meshes is very similar to wearable assets. So, the same package type is designed to work with both.
Click Add New Package. This action creates a dedicated folder for your assets (e.g., Plugins/Wearable_MyCustomCharacterMesh).
If you're using a character pack acquired from Fab, just simply move textures, materials and character mesh into your package folder. Otherwise, if you have an .fbx file to import into project, import it directly into the created folder. Fix redirectors if required.

Note

Alternatively, you can also right click to your pack folder imported from Fab and select Convert to Package (Wearable) to create a package in-place. In that case, steps 2-6 are not required.
Optionally, you can also import a thumbnail image for your custom character mesh in the same folder.

3. Setting Up Your Custom Character Mesh#

3.1. Unreal Engine 5 Rig Based Character Mesh#

If your character mesh is using same skeleton with Unreal Engine 5 Manny/Quinn and has similar proportions with them, you can directly use your mesh without need of runtime retargeting.

Right Click to your character skeletal mesh and assign SK_Unified as target skeleton. This ensures your mesh is encoded with the project's main skeleton asset.
If you get errors about bone merge process being failed or missing bones on target skeleton, that means your character mesh is not compatible with this method and you should follow thesteps in 3.2 instead.

3.2. Custom Rig Based Character Mesh#

If your character mesh is using a custom rig (including old Unreal Engine 4 mannequin skeleton), it will need additional steps to set-up an IK Rig retageter to get it compatible with HELIX characters.

Warning

Please note that runtime retargeting has an additional CPU cost per character rendered on screen. If you're planning your mesh to be used by mass number of characters in your world, please prefer rigging it with Unreal Engine 5 skeleton and follow the steps in 3.1 to directly use it without need of retargeting.

Warning

Ensure all of your skeleton bones have unit scale (1.0). If your character bones were scaled inside Maya/Blender during rigging (especially the root bone), this is not supported and your custom mesh will fail to retarget animations.

Right Click to your custom character mesh in content browser and select Create -> IK Rig. IK Rig is asset is used to define bone chains and IK targets to use during retargeting process.
Open the IK Rig asset you've created. Then click Auto Create Retarget Chains and Auto Create IK buttons on top bar in order. Unreal Engine is usually good at auto detecting your bone chains and automatically define them within the asset.

Warning

If you click Auto Create IK button multiple times by mistake, this might create duplicate IK targets, and they should be removed back from skeleton hierarchy panel and Solver Stack tab on the left side.
Ensure if the generated bone chains look correct on the right panel, and your character got yellow cubes on each hand and feet. Those cubes represents IK targets. If auto generation was successfull, pulling these cubes should move your charater limbs without any visual issues on execute IK body correction on top of it.
If there are issues with auto generated bone chains or IK targets, this usually happens if your character has an uncommon bone naming style or hierarchy, and you need to manually create each bone chain for your skeleton. Please check IK Rig Documentation for more information about manually setting up an IK Rig asset for skeletons.
After IK Rig asset is ready, we need to create an IK Retargeter asset to define how animations should be retargeted from HELIX character base mesh to your custom mesh. To do that, Right Click to an empty space in your package folder, and select Animation -> Retargeting -> IK Retargeter. Open the created asset.
Select IK_Unified_CosmeticsRetarget as Source IKRig Asset. Select either SKM_Manny or SKM_Quinn as Source Preview Mesh according to closest one to your custom mesh proportions for better results. This property will define the source skeleton we'll retarget the animations from during runtime.
Select the IK Rig asset you've just created on previous steps as Target IKRig Asset. This property will define the target skeleton we'll retarget the animations to during runtime.
Both characters now should be visible on the preview panel. You can tweak Target Mesh Offset on the right panel to place your mesh near retarget source mesh as shown below.
On the bottom right panel, Chain Mapping tab should automatically match your IK Rig asset bone chains with each other. Ensure each chain is mapped correctly. If there are missing chain assignments, assign the the missing chains manually.
To ensure your IK Retargeter works correctly, go to Asset Browser tab on bottom right panel, and play one of the available animations. If your custom character plays the animations without any visual issues, this means your IK Retargeter setup is ready!
If there are issues with retargeting results, you might need to further tweak your bone chains in your IK Rig and IK Retargeter assets. Please check IK Rig Retargeting Documentation for more information.
Go into your skeletal mesh asset and find Asset User Data property. Click + symbol to create a new asset user data instance.

Warning

Do not confuse Asset User Data with Asset User Data Editor Only. They are separate properties and only the former should be modified.
Select HELIX Cosmetics Body Mesh Asset User Data from the dropdown menu. This asset is used to define how your mesh should be used with HELIX characters during runtime.
Assign the IK Retargeter asset you've created on the previous steps into Retargeter field.
If you need your character body mesh to get retargeted differently during first person view mode, you can create another IK Retargeter asset and assign into First Person Retargeter field.
If your character body mesh has a neck & head section which can obscure camera during first person view mode, add the bone names covering those mesh sections into First Person Bone Hide List field. Usually, you should put names such as head, neck_01, neck_02 etc. in this list.
Your mesh should be ready for runtime retargeting after following those steps.

4. Tweaking Your Custom Character Mesh#

Custom character meshes have additional requirements to ensure they have optimal performance and fully compatible with gameplay systems in HELIX. Those steps are required to successfully package your assets.

Ensure a physics asset is assigned to your skeletal mesh within its Physics Asset property. Then, open the corresponding physics asset and ensure the capsules cover the mesh approximately. This is required for your mesh bounds to be properly calculated for FOV based occlusion. If this is not done properly, your mesh can disappear randomly from certain camera angles during gameplay. Please check Physics Asset Editor Documentation for more information.
In your skeletal mesh asset, make sure you have LOD data generated for your mesh. This ensures your mesh does not negatively impact performance for distant characters using your custom character mesh. You can set LOD count to 4 and click regenerate to automatically generate LODs for your mesh, as shown below. Please check Skeletal Mesh LODs Documentation for more information.
In your skeleton asset, ensure you have required sockets added. Please check Skeletal Mesh Sockets Documentation for more information.
List of Required Sockets
- weapon_l_socket: Left hand socket used in HELIX to attach held items. Usually should be created under hand_l or weapon_l bone of your rig.
- weapon_r_socket: Right hand socket used in HELIX to attach held items and weapons. Usually should be created under hand_r or weapon_r bone of your rig.
- The list will be updated with more sockets in the future

5. (Optional) Post-Anim Physics Simulation Support#

Custom character meshes optionally can simulate post-anim physics with post-process animation blueprints. Please check Rigid Body Documentation and Anim Dynamics Documentation for more information about how to create one for your character if applicable.

Warning

Post-process animation blueprint support is experimental and creators are responsible with ensuring their custom character physics implementation is optimized for performance.

After creating a post-process animation blueprint, assign it to Post-Process Anim Blueprint field of your skeletal mesh asset.
Make sure to also set a LOD threshold for your animation blueprint in the next Post-Process AnimBP LOD Threshold field, according to LOD count of your mesh. For example, if your mesh has 4 LODs, it usually makes sense to set this as half of the value, 2. This will ensure your performance heavy physics implementation won't be executed for non-significant characters on the screen.

6. Finalizing and Cooking The Package#

Make sure all the depending assets by your custom character mesh are placed inside same package folder. If one of those assets are placed outside of the created package folder, cooked .pak file will have missing dependencies and this might cause crashes or runtime errors during playthrough with this package.
Right Click to an empty space in your package folder, and choose Miscellaneous -> Data Asset.
Choose Character Customization Data Asset from the new window. This data asset is responsible for categorizing your clothing and storing the required parameters.
Give it a meaningful name, something like DA_MyCustomCharacterMesh and open. Click + button and choose the Custom Meshes type.
Create a new sub-entry inside your new entry, and give it a meaningful name.
Fill the required parameters for your custom mesh. Usually, you should leave the Head Mesh field empty, and assign your full body custom mesh to Body Mesh field. Choose gender type for the one closest to your character mesh body proportions. This will ensure the correct base mesh is used while playing animations for your custom mesh.
Return to the HELIX Packaging Tool window.
With your package selected, click the Package button. This process will cook your assets into the final .pak file format required by the HELIX Creator Hub. This may take some time.
Once cooking is complete, a file explorer window will automatically open, displaying your final .pak files. Your custom character mesh is now ready to be uploaded to the Creator Hub!

7. Testing Your Custom Character Mesh#

1. In Creator Kit#

This method doesn't require you to cook the package on the previous steps. As long as you placed all the required assets in your package folder in Creator Kit, and created the data asset as explained above, it will automatically become available for editor playthroughs.

Press play in Creator Kit editor, and press P button to show the Character Customization UI for your character.
In the shown UI, you should be able to navigate to your new custom mesh in Custom tab and click on it to test on the character.

2. In HELIX#

Create a draft world and import the .pak file you've cooked in Creator Kit.
If import was successful, you should see the corresponding custom character mesh assets on left panel.
Importing also makes your custom character mesh automatically available in Character Customization UI. You can go back to the game from build mode, and press P button.
Your imported custom character mesh should be available in the Custom tab.

6. On Your Own#

Once you've followed these steps, uploaded your package to Creator Hub, and imported it into your world, your new custom character mesh will be available for players joining your public world!