I have a rounded square which I created by using Stylize/Round Corners effect on a standard square as recommended here. Don’t worry about the other three squares, we’re just looking at the left hand one!
Now I want to take a portion, (roughly but not exactly half) of that square and make it a darker colour.
To do this I am drawing a shape with the pen tool, diving the object, then shading I would shade the newly created shape darker, but of course, when I divide it, the rounded corners “pop” onto the new portion!
I am pretty sure my workflow is completely wrong. I am NOT an Illustrator pro 🙁
Step 2 – I draw the darker area as a kind of “mask”
Step 3 – I divide so I can have a piece of square to shade darker, but rats! I am sunk all ways round. I can’t even make the darker portion have rounded corners as I only need two!
Object > Expand Appearance on the rounded shape before performing Pathfinder operations. This will “bake in” the effect and make the rounding actually part of the shape rather than an effect. Note the change in the path after using the Expand Appearance command.
This does mean the rounding is no longer live and adjustable. Anchors and Beziers are created and the rounding becomes a standard path.
Source : Link , Question Author : mayersdesign , Answer Author : Scott