I've just recently started to mess around with Forge and I've managed to get my own furnace going with a custom GUI, etc. Now I'm going to make a start on a new mod that will add a few machines, etc.

 

My question is, should I use metadata or a tile entity to store the rotation of my furnace? I plan to add several furnace-like blocks and it would be nice if they could all share the same block id with different metadata per machine, like wool blocks.

The problem is, I use metadata already to store the furnace's rotation and on/off state. (0-5 is each rotation then 6-11 is each rotation when burning) and metadata only goes from 0-15.

 

Should I instead try to use tile entities/NBT to store the rotation and on/off state of my machines instead and use the metadata for different machines. I'd like this to work because the less block ids, the less conflicts, etc. But is this recommended?

If you want to use one blockID for all furnaces cases then yes it's applicable to put the rotation and glowstone into the tile entity and have the metadata represent the furnace type. Remember, while a block only have one global instance, tile entities do not and thus can store any data you need on a per-block basis. As far as I know there is no drawbacks to this.

Ok I'll be using Tile Entities then, thanks for the info!