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Customisation - Retargeting Options
When adding a new character mesh, you will often have to retarget a skeleton to use it. There are several approaches to this, and the process will differ between UE4 and UE5.
Note that when retargeting animations, especially precise animations like those required for First Person games, results are rarely perfect, and animations should be created with the intended skeleton for best results. To help with this, I have designed this asset to be as approachable as possible in this regard, with only one single frame base pose required for each weapon mesh, which the rest of the system will adapt to.
With this in mind, below there are several guides for the various methods of retargeting to get FPS AnimBP to work with your character meshes. There are pros and cons to each approach, and some fiddling may be required based on your specific mesh. You can contact the developer in the Enrapture Games discord channel here for further assistance.
Retargeting Options - UE5
For meshes that are of similar proportions to the default mannequin skeleton, you can delete the skeleton of the mesh you wish to retarget. In the popup window the appears, in the bottom left, choose FPS_SK_Mannequin_Skeleton to replace references. This will essentially replace the deleted skeleton with the correct skeleton in all animations and other files without the need for retargeting.
Please note: I cannot guarantee perfect results when doing this for skeletons with very different proportions to the base mannequin skeleton, however it should be fine in most cases. See: The male vs female mannequin meshes used in this asset.
For more advanced retargeting options using the new UE5 IK Rigs and retargeting system, stay tuned as I continue to investigate a reliable way to achieve this.
Retargeting Options - UE4
Choosing a Method
Unless your skeleton has additional bones that must be kept, I highly recommend using a method that does not involve retargeting the AnimBP itself in UE4, as this is a tedious and messy process to get all the animations retargeted properly. Below are some easier approaches for most situations, and finally a guide for retargeting the while asset the hard way at the end for those that need it.
Retarget to Another Skeleton
You can take an existing skeleton and retarget it to the FPS AnimBP skeleton, which will avoid the process of retargeting the AnimBP itself. First, make sure the Humanoid Rig is selected in your skeleton’s Retarget Manager panel.
Next, you can right click on your skeleton in the Content Browser and select Retarget to Another Skeleton. Select FPS_SK_Mannequin_Skeleton from the list on the left and click Retarget. All meshes that used the old skeleton will now work with FPS AnimBP.
Assigning The FPS SKeleton to Your Meshes
Right click your character meshes, select Skeleton -> Assign Skeleton, choose FPS_SK_Mannequin_Skeleton for each one.
Importing Meshes Using the FPS AnimBP Skeleton
This is the easiest approach. If your mesh is already inside a UE project, you can export it as an FBX. Then you can import this mesh to a separate folder, and in the import window, select FPS_SK_Mannequin_Skeleton
If you have exported your mesh from UE first, you will also want to turn off Material imports. You can also turn off Create Physics Asset and select the existing Physics asset for that mesh in the expanded Mesh section. If you are importing the mesh fresh, you can leave these options as default.
Turn off Material Import if you already have materials for your mesh
If selecting an existing physics asset, only select a physics asset that matches the part of the body you are importing. Arms physics asset for the arms mesh, for example.
You may then need to assign materials to your mesh in the Asset Details panel after opening the new mesh.
This mesh will now be ready to use within FPS AnimBP.
Retargeting The Animation Blueprint
There are some situations where this may be the only solution, though it is long and can frequently suffer from issues with the final result.
Due to UE4 not allowing mass retargeting of animation assets and the animBP at the same time (aside from assets directly referenced by the animBP itself), this is quite a tedious process. Any references to animations outside the AnimBP will need to be manually updated, the skeleton will need several curves and virtual bones added, and a lot of duplicate animations will need to be consolidated.
Even after all that, the result may not be perfect if your mesh has different proportions to the base mannequin until you replace the base poses with your own that are made for your mesh from the beginning. The main culprit here is the ik_hand_gun bone being given a slightly incorrect rotation in some situations, resulting in the ADS pose not allowing perfect sights alignment with the crosshair.
So if you're committed to this method, buckle up, you’re going to be here a while. I highly recommend making a backup of your project before continuing.
First, make sure your target skeleton has the Humanoid Rig selected in the Retarget Manager panel.
Then in the Skeleton Tree panel, click Options and turn on Show Retargeting Options.
Right click root and select Recursively Set Translation Retargeting Animation. Then right click pelvis and select Recursively Set Translation Retargeting Skeleton.
On the FPS AnimBP skeleton, do the same, except this time just right click root and select Recursively Set Translation Retargeting Animation and leave it at that.
Do the same for ik_foot_root and ik_hand_root and save your skeleton.
Next you will need to add a virtual bone. Right click head, select Add Virtual Bone, and choose ik_hand_gun.
Next, you will need to add a few curves to the skeleton. Open the Anim Curves panel in the skeleton window, and add the following curves by right clicking and selecting Add Curve:
Curve
ArmsAdditiveStrength
LeftHandBasePoseOverride
Next, it’s time to retarget. This will need to be done in multiple parts, which will result in several duplicate assets being created. We will get to consolidating these duplicates after retargeting.
First, right click FPS_AnimBP_Character in /Animations/Character and select Retarget Anim Blueprints -> Duplicate Anim Blueprints and Retarget. In the window that opens, select your target skeleton in the list on the left, and choose a destination folder with the Change button in the bottom right. Choose a different folder than the one the animBP is already in to keep the retargeted assets separate from the originals. In this example, I have chosen to create a new folder in /Animations called Retargeted. Optionally, you can add a Prefix or Suffix to the new files' names for easier identification.
This will retarget the AnimBP and all its referenced animations and place the duplicated files inside this Retargeted folder. At this point though, only about a third of all the animations have been retargeted, so we’ll need to handle the rest manually.
Go back to /Animations/Character and select all files except FPS_AnimBP_Character. Right click on one and select Retarget Anim Assets -> Duplicate Anim Assets and Retarget. Follow the same steps as above to place the new files in the same location as earlier and click Retarget. Now all the animations have been retargeted, but there will be several files that have been duplicated twice that will need to be taken care of. This is a simple process, but will need to be repeated many times. I did warn that this will be tedious.
You will need to look through all the retargeted and find any files that have been appended with a number.
Select each of the identical files, right click one and select Asset Actions -> Replace References. In the pop-up window, select the file without the number appended to its name and click Consolidate Assets.
This will delete any unnecessary duplicates and set all references to them to a single file. Repeat this process for all doubled up assets. There will be a lot of them.
Next, you will need to swap out all the animations listed in DT_WeaponAnimationSets with the matching retargeted version.
You can tell identically named assets apart by hovering over them and checking the Path leads to your Retargeted folder.
Lastly, there are a few loose references that also need replacing. Inside the newly retargeted FPS_AnimBP_Character, replace the two references in the select node inside the Throw Grenade function under the Interfaces section.
There is also one in BP_FPS_Character in the V / Gamepad Right Shoulder Action Input event for melee.
You should finally be done at this point. Congratulations, take a breather. You did this the hard way. If everything works correctly now, you can continue ahead.
If there are slight quirks, such as ADS not aligning correctly, you will have to create your own base poses with your own skeleton before it will work right, as the default poses were made with different proportions. Creating poses this way is recommended anyway in order for your character to hold your custom weapons right, so this isn't an extra step, however it can be annoying to encounter this problem anyway.
I will have tutorials on creating base poses in Blender coming soon.