I was very happy with how my work turned out in the Puff app. There were quite a few limitations on the meshes and skeletons that were later exported into the engine, but I think in the end it worked out well, even with those limitations.
I was a Senior Artist while at Padworx, but mainly that meant that I was the Lead 3D artist and Lead Animator.
All 3D and all animations were done in Blender, which proved to be incredibly versatile and forgiving.
The engine used for this app was Unity, and all 3D and animations were created with Blender. Unity itself is a great engine for artists to work with. It may not be open source but it is affordable.