Using inner and outer curves to create an icon

Question

I've recently come into working with Adobe Illustrator to create icons and I was wonder how I could replicate this pre-made icon I found.

I originally thought of using two rectangles and joining them using shape builder and then manipulating the rounded corners but the two lower corners on the top rectangle need to be inward and the top rectangles can't round as far as is needed.

Then I went ahead and just made the top rectangle smaller and tried to use the pen tool to make the inner curve. This sort of works but it doesn't line up right and it leaves weird strokes behind.

What would be the best method to go about creating this simple shape in Illustrator?

Answer 1

The base shape is not actually what you describe. The top part is actually trapezoidal as the sides are slanted.

Answer 2

Round the top and bottom rectangles separately, as much as they need.

Make the top rectangle a little taller than you otherwise would because you'll need to lose some height where they overlap to hide the rounded corners on its bottom.

Expand both.

Put them in position and use pathfinder Join.

Select the two sharp corners where they join with the white arrow and use the "convert anchor point" to rounded:

And then "Show Handles" next to convert anchor.

The corners will look bad:

On each point: Use the handles, drag straight out horizontal holding shift to restore the curve. Then with the white arrow tool select the point and use the arrow key to tap it out away from center. Count the number of taps so you can do the same thing to the other side.

One side done:

With the handles and position of the anchor point you'll find you have complete control of the curve, roundedness, size and location.