Automated Foot Sync Markers using Animation Modifiers in UE4.16

[ShocapEnt]

Just took the totally awesome new Animation Modifiers system in UE4.16 for a spin.

It took me about 30 mins to create an automatic foot sync marker tool with support for forward, backward and strafing movement all in blueprints, no C++.

[video]Automatic Foot Sync Marker Placement using Animation Modifiers in UE4.16 - YouTube

[EGJurre]

Glad you like it!

[FS_Creations]

Would you mind giving a few details on how it works/what it does? I couldn’t find information anywhere.

Thank you!

// Edit: In case someone wonders about this functionality, this is an excerpt from the ue4 roadmap:

Descripción
Animation modifiers are a new type of native and blueprint class, they allow users to apply a sequence of actions to a given animation sequence or skeleton. A native or blueprint Animation modifier should always implement OnApply and OnRevert, the former allows the user to change, add or remove data from the animation and the latter is supposed to remove previously applied user changes. This means the user has to ensure that the state of the animation is set to the original after OnRevert has been called.

New tab in Skeleton and Animation Editors
Accessing and applying animation modifiers is done through a new tab which can be found in the skeleton and animation editor. Animation Modifiers can be added to a USkeleton or UAnimSequence, in case of the sequence it is only applied to the sequence itself. In case of the Skeleton it is applied to all animation sequences which are based of the skeleton.

New Editor-only blueprint functions
A new set of functions to access specific animation data has been added, they’re contained by a new editor-only function library (Animation blueprint Library)

[cyaoeu]

Very cool. I had trouble finding this myself too but you just make a new blueprint and search for modifier in the classes and it’s there. Then just add the events and the new animation library nodes.

[ShocapEnt]

I’m packaging up the Sync Marker Automator as a plugin which I’ll make available for anyone interested in seeing how Animation Modifiers work.

[anonymous_user_416b781b]

Very neat!

Is there a way to calculate the current bone location inside the animation modfiier blueprint? My animations are only using bone rotation, and thus have no position information.

[FS_Creations]

Hey guys,

Can anyone provide a quick explanation on how to use these for foot placement?

I’m trying to sync the feet on running and stopping animations and I still can’t figure out how. Thanks in advance!

[Cpt.Trips]

@EightyGee;704218

I’m packaging up the Sync Marker Automator as a plugin which I’ll make available for anyone interested in seeing how Animation Modifiers work.

Hi EightyGee, Any news on this?

[OptimisticMonkey]

This looks really cool - I started down the path of building my own AnimationModifier, but got stuck…

Are there any examples or documentation that anyone knows of?

[anonymous_user_7e37e9fb]

I didn’t see any documentation on it either but it is a very useful feature that I’ve used in other animation engines and that made me want to explore it right away. Two things to get you going:

1. Create a new Blueprint class, find the Animation Modifier type in classes.
2. Use the Event On Apply that has an output Animation Sequence to feed into the ‘Animation Blueprint Library’ operations.
3. Do a ‘Does Curve Exist’ and a branch to remove the curve and then add it.
4. A gotcha that I didn’t realize was needed, when you get the pose transform of a bone it will be local space, you will need to do a manual transformation of that to component space. I did that by using the Find Path to Root which generates a list of bones, you can send that to the GetBonePosesForFrame which gives you an array of poses that you can use in a ForEachLoop and then do a ComposeTransforms with a temporary transform (initialized as identity) as the A input and Output. Would help if there was a GetComponentSpaceBonePoseForFrame instead, that would save time.

You also need to do a little bit of management between frame and time because setting a key uses time.

[Tylrin]

Hey EightyGee how did you calculate the lowest point for the feet? I am having some probems with it. Would be grade if you would give me an answer. I already know how to use the AnimationModifier but the math is giving me some problems.

My Idea would be to compare the Z location of the feet with the previous and next frame location, but I haven`t tested it yet.

[ShocapEnt]

I actually don’t use the lowest point for the foot, but rather the frame at which the foot goes from being in front of the root to behind the root (in the direction of travel) which is the point at which most of the character’s weight should be over that foot, and thus, the most planted.

[ShocapEnt]

My apologies, for the huge delay in releasing the blueprints - I’ve been crazy busy with a number of UE4 projects. Good news is that I’ve made quite a few improvements to the Foot Sync Automator, including simplifying the workflow (you no longer have to indicate the axis of travel) as well as support for arcing motion (like lean circles). I promise I will make the blueprints available for download very soon!

[senorsean32]

EightyGee, is “very soon” over yet?

[gportelli]

Hi guys! Thanks for the info in this post.
I’ve just written an article on my blog and created a sample project on github with an animation modifier script similar to the one shown in this thread. I hope you find it useful.

http://www.aclockworkberry.com/automated-foot-sync-markers-using-animation-modifiers-unreal-engine/