So I’m looking to learn about characters and animation in UE4. I had a few questions I wanted to ask before I began.
I’ve read on the blog in the comments section that retargeting doesn’t work in 4.11. This is the version I am using. Is this true?
I think I have an understanding on what retargeting does (Using animations for characters with different size/proportions). I can’t seem to find anything that explains how to use the same skeleton for different sized characters. i.e. Do I resize the skeleton in my modeling package, export and then retarget in UE4? How does fitting the skeleton to the character in the first place work?
Yeah unfortunately. I believe it ahs to do with the lack of scripting capabilities. Student version (which I am using - I’m a student) has got some issues as well. I believe somebody ported the tools to blender but I am not sure about how good the implementation is because ART gets updated ratcher frequently (see Pinned posts on animation).
Nevertheless, watching these tutorials gives you a better understanding of how the system works. Retargeting is just something used so that you can reuse existing animations for other characters with the same core skeleton hierarchy. For example if oyu have got some extra hair bones, you can still use the default manequinn’s animations but the hair are going to stay still. This applies to different scaled skeletons (short-tall-fat characters). The offsets that are going to be used in order to retarget the base animations for these new skeletons are calculated from differences on the default pose. The tutorials cover that more in depth than me. You might also want to check out the animation part of some 3rd party tutorial series and the livestreams in order to get a better understanding of how the animations scale inside the engine, like this one : Ratchet and Clank Guns, Mechanics and Gadgets - Programming & Scripting - Epic Developer Community Forums (Only the animation parts | I provide the animations for free if you want to mess around )
Well like all things in UE4 there is more than one way to do the same thing but a few tips/guidelines.
The animation has to match the rig based on a naming convention. If you have a bone called hips containing an animation track when imported the animation will be applied to any object being used as a control object called hips. In UE4 if your hips bone is called pelvis you then have to re-target the hips animation data to the pelvis which creates a new animation set converting the naming convention from hips to pelvis including scale transforms that if applied to an under-scaled rig (different character size) will add the keys as an absolute value which will result in the character model stretching.
You can solve the problem by changing the re-targeting of how the keys are translated so that scale keys are additive and not absolute.
My opinion though is re-targeting in UE4 is just there as an option if a better authoring solution is not available. In my case I use Motion Builder for all of my animation needs that makes re-targeting a snap and can export animations out of UE4, edit as required, and export it to any character I wish. Granted it’s an expensive solution and another tool to learn but makes short work of what usually turns into patch work solutions that are more or less band aid workarounds.
Starting out though I would recommend that beginners start by using the Epic preferred rig to quickly test out a few different configurations to a usable source chain to work out their preferred workflow.
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