Animation Re-targeting with Unreal using Mixamo assets

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Hey guys,

Today I have another tutorial for you, this time discussing how you can import new animations into Unreal Engine and re target them against your character.

For my example I will be using a character from Mixamo, which is a site support by Adobe that has various 3d models and animation resources for folks to use. Since the animations come with their own skeletal definitions you have to re target them otherwise they will be unusable when you bring them into Unreal.

You can also find the source code used in this tutorial on my GitHub page.

In addition to the video here is a quick map of the bones from the Unreal Mannequin and how they map against the Mixamo model.

Also a few more resources from Epic about animation re targeting.

Thanks for taking a look and stay tuned for more.

Unreal – Base


Root Hips
Pelvis Hips
spine_01 Spine
spine_02 Spine1
spine_03 Spine2
clavicle_l LeftShoulder
UpperArm_L LeftArm
lowerarm_l LeftForeArm
Hand_L LeftHand
clavicle_r RightShoulder
UpperArm_R RightArm
lowerarm_r RightForeArm
Hand_R RightHand
neck_01 Neck
Head head
Thigh_L LeftUpLeg
calf_l LeftLeg
Foot_L LeftFoot
Thigh_R RightUpLeg
calf_r RightLeg
Foot_R RightFoot

Unreal – Advanced


index_01_l LeftHandIndex1
index_02_l LeftHandIndex2
index_03_l LeftHandIndex3
middle_01_l LeftHandMiddle1
middle_02_l LeftHandMiddle2
middle_03_l LeftHandMiddle3
pinky_01_l LeftHandPinky1
pinky_02_l LeftHandPinky2
pinky_03_l LeftHandPinky3
ring_01_l LeftHandRing1
ring_02_l LeftHandRing2
ring_03_l LeftHandRing3
thumb_01_l LeftHandThumb1
thumb_02_l LeftHandThumb2
thumb_03_l LeftHandThumb3
index_01_r RightHandIndex1
index_02_r RightHandIndex2
index_03_r RightHandIndex3
middle_01_r RightHandMiddle1
middle_02_r RightHandMiddle2
middle_03_r RightHandMiddle3
pinky_01_r RightHandPinky1
pinky_02_r RightHandPinky2
pinky_03_r RightHandPinky3
ring_01_r RightHandRing1
ring_02_r RightHandRing2
ring_03_r RightHandRing3
thumb_01_r RightHandThumb1
thumb_02_r RightHandThumb2
thumb_03_r RightHandThumb3
ball_l LeftToeBase
ball_r RightToeBase

Unreal C++ with CLion 2018

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Recently I started playing around with a few alternative editors to Visual Studio Community 2017, specifically Visual Studio Code and CLion.

Coming from a Java background it was nice to see that the JetBrains folks have also brought their IDE wizardry to C++ in the form of CLion.

Please note that I am running this setup with the following app / os versions but with some minor tweaks this should be transferable to macOS and linux.

  • Unreal Engine 4.20.3
  • CLion 2018.2
  • Windows 10

In order to get unreal going with CLion you need to do a few things

  • Ensure that you either have Visual Studio Community 2017  installed or alternatively just the Visual Studio Build Tools as you need something to still compile the code.
    • CLion should automagically recognize what you have installed and assign the correct compiler configurations
  • Download the latest and greatest version of CLion
  • Once installed / setup open it up and navigate to the plugins panel ( Settings -> Plugins )
  • Install the Unreal Engine SDK Support Plugin

At this point we need to setup the Unreal side of the things

  • Open Unreal Editor ( source or binary doesn’t matter )
  • Go to Edit -> Editor Preferences

  • Then go to General -> Source Code -> Source Code Editor and select CLion

  • Once this is done you should now be able to generate a new CLion project  using File -> Generate CLion Project

  • This generation step will take a few seconds to complete
  • Once complete you should restart Unreal Editor before opening up CLion
    • NOTE: not sure why this occurs but generating the project and launching it immediately does not correctly configure it. I found that making adjustments to the CMakeLists.txt file and setting the build process to Release prior to launching CLion seems to clear up a lot of things. See below for details.
  • To open up CLion go to File -> Open CLion

At this point Unreal should be launching CLion and presenting you with your project structure that looks similar to this.

Almost there, we just have a few more things to complete before you are able to get back to building your game:

  • Ensure that you are picking your Project + Editor as your Build Target. This is so you can compile in CLion and get hot swapping in Unreal Editor.
  • Alternatively if you are building different targets make sure those are selected.

  • Ensure that you mark your Source folder as part of CLion project definitions so intellisense / autocomplete works correctly
  • This is not required but helps with navigating your project

That’s it !

And that is it as far as configuration goes. You should be able to build your project using CTRL + F9 and see your changes reflected in the Unreal Editor / your game.

The compile times are similar to Visual Studio but the richness of the CLion tool suite makes development a lot easier to traverse. Specifically have a look at the various shortcuts that come with CLion.



Additional Troubleshooting

There are a handful of issues I ran into while compiling this article. If you come across anything similar here are a few instructions that should hopefully help.

Dealing with invalid CMakeLists.txt file

The CMakeLists.txt file when generated by Unreal sometimes will contain non escaped backslashes, \ vs \\ , which will have to be adjusted manually.

Example of invalid backslashes

Corrected versions.

Command line error D8049

If you come across this error when trying to compile your CMakeLists.txt file it is most likely tied to building with Debug instead of Release.

To correct go to Settings -> Build, Execution, Deployment -> CMake and change the Build Type from Debug to Release.


Deleting CLion references and changing back to a different editor

In case you are not happy with CLion and want to revert things back to use Visual Studio I recommend cleaning up the files the CLion integration generated.

Specifically the following folders / files inside of your root project:


Once this is complete you simply follow the initial set of instructions but instead of picking CLion just select Visual Studio. This should then give you the option to re-generate the Visual Studio project within Unreal Editor ( File -> Refresh / Generate Visual Studio Project )