I delete half the basin.
I use the top shape as a guide and snap the last row of verts on my sphere to the top's edge verts..
Once I have matched all the points of my basin to the top shape, I delete the top shape. I no longer need it.
I duplicated the half and negative-scaled it across the x axis. Remember to freeze transforms and flip the normals.
Now I unhide the sides of the sink.
The pieces fit perfectly but there are T junctions because of how I built the basin surface.
T junctions are bad because they cause "seams" in game that flicker.
Even if we didn't combine these surfaces they would flicker.
T junctions get addressed by either combining verts on one surface or cutting the other surface to create extra verts--
both surfaces must have the same number of verts where they meet.
I combined a couple verts on the basin surface.
I then sliced the sink side surfaces in half.
Now there are no more T junctions.
