okay so i'm trying to make a cake like the soap bar from the movie "fight club" well i'm trying to figure out how to do an indention for the writing like the soap usually is
something like that
I think you might have to carve it into the cake. I would do a stencil first and transfer to the surface then carve it.
I might be tempted to try making my fondant thick on the top, then using a tool of some sort (don't know if there are v-shaped cake tools--sterilized woodworking tool maybe?) to carve in the letters. Using a stencil is a good idea if you don't think you could eyeball it. Does this make sense?
I looked at google images, and to me, it doesn't look like the words are indented at all. It looks like they actually stick out from the bar of soap.
I agree that the letters are actually raised rather than indented. I would roll my fondant rather thick and cut the letters from that. I might also do a little shading around my letters so they really stand out from the base.
Another idea if you want the indented look is to use 2 layers of fondant. Cut the letters out of the top layer of fondant and spread over the 1st layer.