How to fix shoulder and Hip deformation problems without adding new bones

Hi I created a human mesh in blender which I want to rig and export to ue4 for animations my project in ue4 is for mobile which does not allow more than 75 bones for rigging and as expected after creating the rig for my character including the IK I ended up with 72 bones but I still have some bad deformations in the hip and shoulders I want to ask if there is anyway to fix this without increasing that number of bones

Hello and welcome to the forum!

First off, lemme say that I’m not a game engine person. I model, rig, animate in blender only, but I know game engines generally don’t support all the tricks that blender has to fix deformation problems.

Having said that, I fully believe 90% of deformation problems can be fixed by using proper mesh topology and weight painting. The mesh should have edge loops flowing in specific ways to help the mesh deform properly in the hip & shoulder areas. This also applies to knees, elbows, fingers, etc… This has all been studied to death and results have been posted to the net, so google it. The 2nd crucial part of this is weighting the mesh to the bones. IMO, blender’s auto weighting only gets you about half way there. You have to go in and touch-up the weighting of the mesh to the rig in extreme poses to really get it right.

If proper topology and weighting doens’t fix the problems, then you might want to look into shapkeys. I think most game engines support them.

As a game dev, let me ask you, would it be more desirable to have an animation friendly rig with unlimited amount of bones that would export out within the game engine parameters of less than 75 bones?