I have been having an issue with getting a squash and stretch rig to behave correctly in UE4 (version 4.10 and 4.12) after exporting from Blender v2.76. Particularly the issue is that the child bones for a character skeleton inherit the scale of the squash and stretch bones. As you can see here:
The setup is two stretchy bones in the leg then two non-stretchy bones in the foot, then there are some extra bones to form a pelvis and root bone. What is odd is that the foot bone appears to be inheriting the scale of the stretching shin bone.
Originally I created a simpler squash and stretch rig with one stretchy bone weighted to the cube and one non-stretchy child bone weighted to the sphere, shown below:
In this case however the child does not inherit the scale, so I am not sure why the leg behaves the way it does.
I have a feeling this is an issue to do with the IK setup on the leg. From other threads I have browsed it seems this seems to be an issue on the Blender export side of things. But perhaps there is a way to stop bones inheriting the scale values of parent bones inside Unreal?
If anyone has some advice on how to solve this I would be very grateful. Thank you.
[NOTE] I have posted this issue to Unreal Forums and since then have talked to my lecturers at Uni who think this is definitely an export issue and that the foot bones are storing some transform information that is not being displayed in Blender but when in Unreal the engine accounts for that. In which case I will run some tests and import these files into some other 3D packages and see what I get.