I'm trying to make a boss extrude flushed with a surface:
However, if zoomed in, there's clearly a gap:
Does anyone know why there's a gap when the two faces should be flushed (and merged)?
Any thought appreciated. Thanks.
You picked the wrong edge
See att. part - the gap is gone
You need to move the sketch back to fill the gap
As John Stoltzfus says, the back edge of your extrude sketch is not far enough back. You need to make it coincident with the top edge of the up to surface or drag it inside the corner edge & or dimension it to the corner edge. The gap is because the extrude goes up past where the fillet starts to bend away from it as you can see in the bottom image.
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