How to modify corner radius on rounded rectangle in Photoshop?

Question

I develop puzzle game and I want to create grid with smooth edges like this image:

How can I make rounded rectangle with corner inside it (the radius with negative sign)?

OR Anyone can help me with the best way to make this grid ?

Answer 1

In Photoshop this can be achieved by using Boolean Operations on a Live Shape object.

1. Draw a square with rounded rectangles.
2. Draw another shape on the same shape layer by holding shift while you draw it.
3. Position the second shape so that it overlaps the first. The areas that overlap will be the areas 'removed'.
4. Select both shapes and click the Subtract Front Shape button in the properties panel.

Here's a screenshot demonstrating the final product:

The Subtract Front Shape button is the selected button within the four button group at the bottom of the Properties panel.