What I'd like to do is make the top sides straight horizontals, with the 10deg curved verticals and rounded corners on the top left and bottom right. When I tried doing this by drawing a straight line off the end of the quarter circle, it produced a bump where it connects.

In other words, how can I make a curve that perfectly matches an angled line, the same way the quarter circle in the first image perfectly matches a straight vertical line?

If it requires the use of the pen tool, how can I make sure it is mathematically correct?

The trouble with corners...

  • 1
    How about drawing the skewed shape without rounded corners first and then round them afterwards?
    – HaraldCFS
    Aug 16, 2016 at 13:23
  • But how can I do that? I do not understand how to draw the curve in the first place. Using the pen tool creates the same bumpy problem as the above example. Aug 17, 2016 at 4:28
  • If you're using Adobe CC , select the shape and there will be little round dots close to the corners. Use direct selection tool (A) to only choose one corner at a time and select and pull the corners you want to fillet. If you're on Ill. 5 (6?) or earlier you'll find rounded corners somewhere in the effects menu.
    – HaraldCFS
    Aug 18, 2016 at 8:16

2 Answers 2


First draw the rectangle. Then, with the white arrow select just the corner node you want to round. Go to convert anchor point (it's in my top bar) the only option will be round.

The corner will be rounded but probably won't look right. Use the handles to bring it back into place. Select rounded corners node with white arrow and tap it towards center of rectangle to bring curve in.

Alternately use the round corners tool. It works on all 4 corners so you have to restore the other two corners. To do this draw your rectangle, copy and paste another one, select either and hit effect/stylize/round corners.

Preview and adjust value until you've achieved sufficient roundness.

Select both rectangles and align them horizontally and vertically. Make sure there's no stroke. Open pathfinder window and hit divide. Erase the corners you don't want.

Select all and hit pathfinder/unite to put it back together.


You can follow two ways:

  • The first one, is to use the round corner tool found in Illustrator CC (you can activate on the control point(s) that you want to edit, and you will see the white pin which allows you to round the corner.

Round corner tool

  • Note that the same option can be found in the properties palette: under the transform section you can find the “Corner shape” box – if you don’t see it and you have a recent version, you might have to click the three horizontal dots

Corner shape location

Hope it helped!

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.