Porting games made for PC to console in UDK/Unity3d

I am now trying to learn game development in UDK and Unity3d, just trying both out, and try to get an idea how they work, and for now im mostly focusing on the PC games..

I want to know, how hard(technically, not legal/licensing stuff) is it to port a PC game that i made in UDK/Unity to another platform such as PS3/Xbox360? is there some kind of option where we can just select the target platform from a combo box and press deploy? or do we need to modify the game for each platform? just give me a rough idea 开发者_高级运维on how it works..

I can only speak on Unity3d. For Unity porting is basically:select your platform and cross your fingers.

(had a nice pic here, but I'm new so I can't post that..)

There are conditionals that can be used for the different platforms and you'll need to deal with the different controls, add rumble etc (though lots of it is abstracted nicely).

Luckily with Xbox and PS3 you won't need to worry too much about assets (if you are initially targeting PC). I currently target Android and constraints are a little tighter( i.e. textures and lighting are much more limited). The nice thing is if it works performance wise on the tablets I'm targeting I know it will work web/pc/mac fine (which I use for demoing the product to clients).

I think at most I spent 30 minutes one time changing camera angles to make things look better on a specific Windows tablet that had a lower resolution than the Android tablets. This was due to short sightedness (it could have been dealt with programatically), but was still quite easy to change then ftp out a special build for the old Windows XP tablets.

So far I've been truly impressed with the cross platform behaviour. That being said, I only target PC/Mac, Unity Web Player and Android so far (I'm set up for iOS but haven't bothered yet).