How to make a connecting 'curve'?

Aditya_Bakshi

Hi,
I'm trying to build a basic stadium model with onshape: https://cad.onshape.com/documents/01c716fbbc93016c0342311b/w/178c8020db5915d50d7a2bd2/e/d965ac6f61a42404fd138b17
So basically what I did is, I created the longer sides by drawing three triangles on the front plane and extruding them. For the shorter sides, I offset the right plane (to have the right position) and did the same thing - 3 triangles and extruding. So that's how I got the basic model.
But now what I want to do is, make somewhat of a curve that 'connects' the open spaces, so as to make the final model look like this: 

 
As you can see, there are those curves at each corner. I want to make those.
So can someone please help me? Thank you. I'm new to onshape. 

lana

Here https://cad.onshape.com/documents/7adfd3d809af5f9676db85b4/w/e1fb8c6611dde9c2917c7e74/e/888c5bd487ab07967862afe7   I've used Revolve to fill in the corners. I also constrained sketches and planes for better alignment and made use of mirror symmetry.