3Ds max animation to UE4.

A description of the practical application would be helpful as there are a few techniques that could be used. Angle deformers are unique to 3ds Max but one could always build their own from scratch but based on the example the easier option would be to build an accommodation into the joint rotation that would maintain volume through the joint rotation.

https://youtube.com/90QsKfOh2UU

The theory is the outer loops will rotate around the joint while the inner loops will compress into one another