I’ve always had trouble getting animations to work without a bone system. I’m trying to do simple animations like a treasure chest opening but have only gotten it to work for one game. I use 3dsmax and export as .fbx, not sure if someone knows how to properly do this?
For simple animations, don’t forget that you can use animation curves in Unity.
To animate the chests seen here, the mesh model was created in two parts, the chest body and the lid. The Lid had the “center point” set along the hinge end, and the animation was created using curves in Unity.