If your buttercream is not smooth the fondant will not be smooth. After I crumb coat I always put on another layer and smooth it. There are several methods to this. I don't have the link but if you go to CC search and type in Melva and smooth buttercream you would probably find Melva's paper towel technique which I use religiously (always use Viva paper towels though - no texture). HTH Maybe someone else can be more eloquent answering your question.
12/3/14 at 12:44pm