When I make a carved cake sometimes there are several layers. They need supported with cardboard cake boards and straws. Do I insert them before carving or after? If they're inserted before how do I deal with them while carving?

I make plenty of those cakes (in my gallery). You do need to support your cakes before carving. Just make sure you cut the dividing board about 1 inch smaller than the cake so when you carve you have enough room to not hit the board. In cases where I underestimated and the borad is just in the way I will use scissors and cut the board so as to not have it sticking out and in my way. Hope this makes sense.

depends on the cake for me...........since I usually carve while my cakes are still frozen sometimes I will just stack them up frozen, carve and then unstack them all and use them as a guid to cut boards.

If there is a LOT of details in the carving and I know it will take a while and my cakes will thaw while I'm carving then generally I will draw out a rough idea of the shape of the cake and cut boards slightly smaller than that, like jobueno said, and then fill and stack and then carve.

Sometimes the boards themselves serve as a guide for me as to HOW to carve to get the shape I'm after.......which is really nice if you're carving an odd shape that needs to be symmetrical to have that board cut out to the perfect shape and then use it as a guide for your knife

HTH