Mixamo is a powerful online tool for quickly rigging and animating 3D characters. However, when you import a Mixamo-rigged character into Unreal Engine, its skeleton may not match Unreal’s default humanoid skeleton. Retargeting allows you to take existing animations (like those from the Unreal Mannequin) and apply them to your custom Mixamo character. In this tutorial, we’ll go step by step to import, rig, and retarget a Mixamo character in Unreal Engine 5.
Step 1: Upload and Rig the Character in Mixamo
1. Go to Mixamo and press Upload Character
2. Drag-and-drop your FBX file into the dialogue box
3. Click on next to begin the rigging process
4. Place the markers on the correct body parts
5. Press next to allow Mixamo to auto-rig your character
6. Download the character by keeping the default settings and using the FBX format
Step 2: Set Up a New Unreal Engine Project
1. Create a new Unreal Engine 5 project using the third person template or open a project
Step 3: Import Your Mixamo Character
1. Right-click and make a new folder to contain your character
2. Drag-and-drop your downloaded FBX from Mixamo into this folder
3. Press Use Pipeline Defaults, leave everything else at default, and press import
4. If textures aren’t applied, you can manually replace them
Step 4: Add a Root Bone to the Mixamo Skeleton
1. Mixamo skeletons often start at the hip bone, but Unreal’s mannequin expects a root bone
2. Double-click on your imported skeletal mesh to open it
3. Click Skeleton → Edit Skeleton
4. Close all bones, right-click → New Bone, name it Root
5. Drag the Hipbone under the new Root bone
6. Press Accept to Accept
7. Change the merge type to merge, then select commit
7. Save the skeletal mesh
Step 5: Retarget Animations
1. Go to Content Browser → Characters → Animations → Unarmed to find the default UE animations
2. Right-click an animation → Retarget Animations
3. Set Target Skeleton to your Mixamo character
4. To export multiple animations at once, select all the animations
5. Click on export animation
6. Right-click on your character folder and add a new animations folder
7. Add a prefix like Character_Animations_
8. Click on export
9. All selected animations are now retargeted to your Mixamo skeleton
Step 6: Replace the Character in the Third Person Blueprint
1. Under the third person folder, open Blueprints → ThirdPersonCharacter
2. In Components, under the mesh section, change Skeletal Mesh to your Mixamo character
3. Under the animation section, change the animation class to the corresponding AnimBP
4. Press Compile and Save
Step 7: Test Your Character
1. Press Play in the viewport
2. Move around; the Mixamo character should now have all default UE animations applied (walk, run, idle, etc.)
3. You can repeat this process with any Mixamo character using the same workflow
Conclusion
Retargeting Mixamo characters in Unreal Engine 5 is a straightforward process once you understand the workflow. This technique allows you to leverage Unreal Engine’s animation library for any custom character, opening up possibilities for prototyping, game development, and animation testing.
By following this method, you can quickly populate your projects with diverse characters without manually creating animations from scratch.