[tjones]

Ok to add the radii at the bottom simply use the Fillet command but first you must combine the sphere and the cube by using the Boolean add.

Do this by simply selecting the cube and one of the spheres then go to Solid>Boolean and select the add.

Do this until all spheres are added to the cube.

Put a very large fillet so the dimply connect smoothly.


So from there you can create 2 squares (one to match your outside solid form and the other much bigger to clear everything) using these squares we will create a surface and then a solid. (This is to trim the outside by using a bollean subtract.)