how do hidden pillars work???

Can I use them in a cake like this and what would i do

Thanks

Yes.
Cut the pillars flush with the top of the cake. each tier is on a plate and the legs of the plate fit inside the pillars in the lower cake.

Ditto what Debi said.. lol

Seriously, when I do a stacked cake I use the hidden pillars exclusively. Makes a good sturdy cake. I have even transported a 3 tier completely assembled and had no problems.

How are hidden pillars stronger than regular wooden dowel rods?

Illustrated common cake support systems:

http://tinyurl.com/y22z72
(With complete and accurate directions.)

If you click on any of the support system pics, more info is given which will probably answer a lot of your questions.

More on SPS system:

http://forum.cakecentral.com/cake-decorating-ftopict-561846-.html
(See Leahs post.)

Illustrated "how to cut level dowels" by indydebi:

http://forum.cakecentral.com/cake-decorating-ftopict-434013-.html

HTH