How do I cut out a symmetrical shape from a layer?

[simpan83]

I have a grey rectangle in a layer (with somewhat rounded corners). Now, I want to cut out lines in this rectangle, making it look like an envelope. The lines need to be perfectly symmetrical obviously. How do I do it?

[Abambo]

Draw one half, copy and mirror.

Copy / paste...

Edit->transform->flip vertical

...and move in place:

[simpan83]

The problem is, I have a rectangle that is grey. It's residing on a translucent background. I want to cut out the lines from the rectangle layer, making the lines translucent as well... But how...

[davescm]

Can you post the image - it is hard to tell without seeing it

Dave

[Nancy OShea]

You mean something like this?  I used a Custom Shape for the Envelope and gave it a gray fill with no stroke.  See screenshot.

[Abambo]

Use your lines as masks. As @davescm​ says, it would come handy to post a screen shot.