Mesh Smooth Issue

Hello everyone, i have an issue about mesh issue, I am using Maya for char animation, I was export only base mesh of char with smoothing groups checked its work fine for me check the pic below

Now same file same setting when i was export rig char with animation from Maya its not smooth on UE4…check the pic below

*** Please any help me to fix that issue ASAP i have project to deliver, thanks in advance *****