Hi,
First timer with UE4 Animations, I am trying to understand the overall facial animation system used for driving amazing animations inside Metahumans. This effort is also to see if there’s a way to create a similar/optimized rig structure for a custom face model & still get it working with the Live Link Face app.
So far it seems that Metahuman requires Morph targets-based animations, but am not entirely sure what purpose Control rig serves. I understand that it is used for improving existing animations based on certain conditions or animation retargeting. Is the Control rig needed to solely support the Live Link face app? For in-game use can we work with just morph targets/bone-based animations?
Any help would be appreciated.
Regards.
1 Like
Hi,
Live Link is able to send floats corresponding to each shape value that the iphone sensor picks up, but in UE, when using MetaHumans, those values are not linked 1:1 to MetaHuman blend shapes, since all the blend shapes that you see on the head are corrective blend shapes ( used for the LOD-1 ).
If you take a look at the “Face_AnimBP”, you’ll notice that after the LiveLink node, there is a “mh_arkit_mapping_pose” where a pose asset is referenced there.
If you open it up, you’ll see that on the bottom left you have the shape names ( from arkit ), while on the right you have the curve name values…so what happens is that, in Maya, using the MetaHuman Rig ( the one you get from Quixel Bridge ) used all the various facial controls ( which are driving the hundreds of joints on the face ) and for each frame a shape is stored.
In the same folder where the “mh_arkit_mapping_pose” you’ll also see an animation called “mh_arkit_mapping_anim”, which is exactly what I said aboive, meaning an animation where, on each frame, there’s a face shape.
This is a brilliant method, since if you have a custom facial rig and you wnat to use LiveLink using the iPhone, you can do the same thing and use the nodes within Unreal to pretty much convert the 0to1 values from the iPhone to a specific face shape you created with your rig ( whether is done with blendshapes or with joints, it really doesn’t matter ).
3 Likes
Thanks a ton! Appreciate the quick response. The overall system is complex to digest for the first time.
I wanted to understand what role then does Control rig plays in this whole scenario? Is it needed to fine-tune animations further? Is it MUST-HAVE component in grand scheme of things?
Also, say I don’t want to use Live Link App then for in-game animations, I can transition between morph targets using a BP, right?
Regards.
You can use Control Rig in different ways, like easely creating animations in-engine, rather than using Maya/MoBu/Whatever software, or drive in realtime your entire character using external data ( mocap suit ).
You can also fine tune your animations ( mocap data ) once imported in engine, using layers to polish the animations, or you can go full dive and create facial animations directly in engine using the Control Rig UI.
To reply regarding your questions as MUST-HAVE, consider that it works only for characters built with control rig, and the whole facial animation rig is, again, built to be used only on MetaHumans, so if you want a custom character, you either get a MetaHuman in Maya and modify the entire thing there, or you just use a default MetaHuman.
So if you’re planning to do custom stuff to characters, you need to pretty much create a custom control rig for your character, and if you’re crazy enough, you can also repurpose the entire facial rig for another character, but good luck with that.
MetaHumans are very usefull both for animation previz and in-game animation creation ( using Control Rig ), so it’s up to you how you want to use them.
Regarding your last question, again the morphs on the Metahuman face are not regular blend shapes, but correctives, so if you’re not planning to use LiveLink ( or you just want to create facial animation from scratch ), you can simply use the facial rig UI that comes with every Control Rig ( drag&drop a Metahuman onto Sequencer and you’ll see the UI ).
2 Likes
Amazing! Thanks a ton. Will take it forward from here 
1 Like