I am really confused, I know that forge automatically assigns ids, but I am afraid that if I make a structure generate, or update the mod. All the blocks will be reset, this is a very big issue as my mod is a build blocks mod. And if the blocks were to be removed then good structures would mess up. Including generated ones, is there any way around this?

ids are not reset if they are already generated, new ids are only generated for the new blocks and items

That is not true. If you remove or add a Block, the other IDs stay consistent (per world, they can be different from world to world). This only works if you properly register your Blocks & Items to the GameRegistry and don't change the name you registered them with.

This has taken a lot of pressure off me, but what about structures that are generated?

There is no mod.blockname.blockid anymore (silly mojang).

Do you not need this anymore, is there an alternative to blockid? And it would be very nice if you redirected me to a generating structure tutorial that is not 1.6.4.