Customization of World

## Structures

Basically, there are a few parts to this.

* First, you have to click a button to customize structures (add/remove structure).
* Second, choose an additional world file if you chose to add a structure.
* Type in the name of a structure block file.

If you just want the same structure all over your world, skip these next couple of parts. If not...

* Choose the loot options of chests if there are any in the structure. Basically, just path to a loot table or select the possible items and their rarity.
* The other option is for various rooms. This brings up a GUI of the structure block files you have (additionally, an "add/remove file" button)
* In this interface, you have a few options: you can choose spots where certain rooms will *always* spawn, rarity of rooms (a 0 guarantees it's generated, but not always in the same place), what rooms other rooms can connect to, generations that occur when they connect, how many times that room can spawn, etcetera.

The final set of options are the rarity, biome, height level (exact y levels, or "underground," "surface," and "sky"), dimension, and identification name for /locate.

## Mobs

As with Structures, you can choose a world file to grab any commands related to the mob in question—so long as the name you typed matches (and you have the correct command you used to summon it in a text box), all of those commands apply as if it were a normal mob. Additionally, you can just type the command and go.

You then decide what biome, depth, structure, dimension, etcetera it spawns in, and a few extra criteria (such as special AI notations) may also come in handy.

Landmasses

I'm not entirely sure how this would be handled, but I'll attempt to propose a reasonable system.

* First, name the landmass you want generated. Later, you can add exactly how and where it will spawn (even in custom biomes) if you use this file name.
* Second, you get a GUI of a typical Minecraft world. It's like a render, and you can swap between generic versions of any biomes (including custom ones). So, this is all well and good, but what does it do?
* You get a Worldpainter—esque tool. With this, you section of various points, noise values, angles, vectors, and various simplifications of the sort. Did I mention this would be in Expert settings for custom worlds?
* Basically, you use these tools, verify (and name) the sections, and get a representation on the GUI. You can switch the biomes (there's also biome-dependent settings) and randomize the generation, to show if the success was a fluke or not.

Congratulations! You have your own custom generation.

## Biomes

This may very well be the most difficult.

* First off, you get a blank plane in the form of the Custom Generation GUI. Wonderful.
* In this, you choose grass color, generations of blocks, noise values, custom generations (along with their rarities), typical depth variations and levels, water pattern and biome-wide water level, which Biomes they can border, their temperature, if they have weather, "lines" of generations which decide how well generations conform to a specific shape (think lines and ranges of mountains), etcetera.
* All of this appears on the GUI. Once again, you can randomize it, turn it into a sub-biome, anything, to get it to your liking. Likewise, you can view surrounding biomes and their conformity to the new biome.
* Less interestingly, you can delete and replace biomes.

Boom, infinite possibilities for world generation—without any changes to the actual terrain! This would do *wonders* for map-making and custom survival. Also, no commands needed for custom mobs!