Rigging for game development - cluster vs joint

[Anonymous]

Hi, I am fairly new to Maya and have been modeling and animating in Blender up to this point. I create assets for Unity game engine, which only supports limited information from FBX files exported from 3d modeling software. Unity only reads information about joint-based mesh deformation - not other types of deformers such as warp, cluster, etc. Additionally, it only allows up to 4 influences per vertex. My goal is to have stylized characters animated well in Unity, and it seems these limitations make that quite difficult. I have heard of others trying to bake deform information from others deformers into blend shapes, but this seems like it will really decrease the quality of deformations in animations. My question is, what do cluster deforms do that regularly joints do not do? Why can't someone just use joints instead of clusters to deform a mesh, since Unity will read joint-based deformations. Is the influence/weighting of cluster deformers different than joints?

Could a rig like this be made using joints and no other types of deformers, with only 4 influences max on a vertex?

https://www.youtube.com/watch?v=B__ZWmRzEsI&t=4s

Thanks

[jmreinhart]

Skinclusters (joints) only allow a total influence of 1 on a vertex, which means joints are competing for influence in areas like the face that require complex control. Clusters have their own weightMap that can be painted any way you want, but it can be hard to balance weights between them since you can only see one weightMap at a time. Also, a single skinCluster is better than having lots of clusters.

You could do a rig like that with only joints if you have great skin weighting and know how to use helper joints. Here is an example of helper joints in a complex videogame rig.

https://youtu.be/myZcUvU8YWc?t=836