RFTools Dimension Enscriber
This machine is where you actually describe your dimensions. It is crafted as follows:
To use it you first have to insert an Empty Dimension Tab which is crafted as follows:
This will be the item in which we will insert all dimlets and create a 'Realized Dimension Tab' that describes our dimension.
If you just want a random world then this is all you need to do. You can just press 'Store' and pick a name for your dimension (input field at the bottom-left) and you will get a totally random dimension.
Otherwise, if you want a little bit more control you have to insert dimlets in the top grid. The order of these dimlets matters. Modifier dimlets (material and liquid) have to go before the dimlet that they affect. Unused modifier dimlets are simply ignored. You can insert as many dimlets as you want but note that not all combinations are useful (i.e. if you put in a 'Void' and 'Flat' terrain dimlet then only one will be used) and the cost of the dimension is calculated from the dimlets that are inserted. Not from the dimlets that are actually used! So inserting too many dimlets will make your dimension more expensive.
If you don't specify a certain type of dimlet then you will get a random selection of that dimlet type. For example, if you don't specify any structure dimlet then you might get a selection of random structures (like village, nether fortress, ...). If you don't want that you have to insert a 'Structure None Dimlet' which will prevent structures from being generated. The same goes for many other dimlet types.
An important thing to realize is that the dimlets that you insert into a dimension tab makes the 'signature' of that dimension. That means that if you create another dimension tab and insert exactly the same dimlets then it will refer to exactly the same dimension. This can be handy in case you want to power a dimension from multiple places (more on that in the Dimension Builder section) which can be handy for very expensive dimensions.
Note that with this dimension enscriber you can also deconstruct a realized dimension tab into its original dimlets and the empty dimension tab. The dimension will not be removed (if you created one) and can still be accessed if you have a teleporter to it. However, it can no longer be powered unless you have another realized dimension tab sitting in a Dimension Builder somewhere. If you accidentally deconstructed a realized dimension tab into its dimlets you can simply construct it again and it will refer to the original dimension (without having to build it again).
This means that if you want to generate another dimension with exactly the same features as before you will need to add some dimlets to change the signature. The best way to do that is by using 'digit' dimlets. These dimlets don't do anything special to the dimension but they do change the signature allowing you to make multiple dimensions with identical features (although randomly generated features may and will differ if you didn't specify them).