Can anyone tell me how to make the box part for a wine bottle cake? The ones I've seen on CC doesn't look like they are just sheet cakes covered in fondant. The corners or sharp and clean. Do you use modeling clay or do you measure and cut panels from fondant and let it dry before assembling?

i made a wine box cake and i cut pieces of fondant the size of the cake and added about an inch more in hight then the cake. cooled the fondant in the freezer for a few mins and then attached to the sides of the cake. when the fondant is cold it's easier to trim if your seams dont line up. i rolled the fondant about 1/4 inch because i painted it which i have found makes the fondant softer. the extra inch gave me room to add a piece of fondant for a cloth and then the wine bottle. (the cakes in my pics if you want to see)
have fun

Thank you BRATTYR.