I have a bridal shower cake I would like to try this on..thank you.
Why would you think it would crack? You can use the diamond impression mat, or the diamond cutter to impress the design on the fondant on the cake.....it should not crack. Just don't press the cutter in too hard!
If you do it while the fondant is fresh and still soft it shouldn't crack.
What Texas said.
Yes, I agree with the others, with most fondant, you must quilt right after applying it, but....not all fondants are the same If you use white chocolate fondant, at least this is true with mine, I have gone an hour later and quilted and had NO cracks whatsoever.
You also might have taken a long time to cover the cake, and your fondant is crusting as it sits.
Hope this helps you a bit....