Dimensions

ReInDev 2.9_03 ships three places to explore: the Overworld (dimension 0), the heavily overhauled Nether (dimension -1), and the Sky, a band of floating islands generated high above the Overworld rather than in a separate world file. Each has its own block palette, fluids, mobs, and ways in.

The Overworld

The Overworld is where you spawn and the only dimension you can set your bed/respawn in. It uses an island-based biome layout (an enormous lookup of island templates seeded per region) rather than a continuous landmass, giving discrete landmasses surrounded by Ocean, Coral Ocean, Coast, and Beach. Surface biomes include Plains, Forest, Flower Forest, Rainforest, Swamp, Taiga, Snowy Taiga, Tundra, Frostland, Mushland, Savanna, Shrubland, the Cacti/Dry Deserts, Mountain, Wasteland, Quickland, Lake, and Islands. It is the source of wood, ores, food crops, and the obsidian and flint-and-steel you need to leave it, and the only dimension where rain and a normal day/night cycle occur in most biomes.

The Sky

The Sky is not entered through a portal. It is part of the Overworld: floating islands generate at very high altitude (the biome manager switches to its floating-island generator above y 384, and the islands themselves populate around chunk-y 36, i.e. roughly y 576). To reach it you simply build upward (pillaring, scaffolding, or water/feather-assisted climbs) until you break out onto the islands above the clouds.

Four Sky biomes tile across the islands, laid out in a fixed grid: Cherry Groves (the dominant fill), Grassy Fields, Stony Mountains, and Icy Peaks (the rarest, scattered through the Stony Mountains). The Sky disables rain. Generation up here scatters lakes, tall grass, and flowers — White Dandelion, Aster (a marigold variant), Violet Rose, and Buttercup. Mobs are sparse and mostly peaceful: Chickens, Moobloom, and Moolip spawn as passive fauna, while the one hostile spawn is the flying Wyvern (40 HP), which dives at players. Falling off an island drops you all the way back to the Overworld surface, so bridge carefully.

The Nether

Reach the Nether the classic way: build an obsidian frame and ignite the interior to open a Portal block. Stepping through teleports you to dimension -1 (a self-contained Hell world with no sky, no sun or moon, a dark-red fog, and no valid respawn — you cannot sleep or set spawn there). It is a ceilinged world capped with bedrock.

The overhaul's signature feature is that the Nether is layered vertically into three bands, each running its own biome map:

• Surface (y ≥ 0)
• Middle (y < 0)
• Lower (y < -64), the deepest and most exotic band

Because biomes are stacked, the same horizontal spot can be one biome on the surface and a completely different one if you dig down. Several distinct fluids replace plain lava depending on biome: ordinary Lava, Acid, and Sanguis (blood) — each fishable for biome-specific loot.

Surface and middle biomes

Lower-layer forests and valleys

• Crimson Forest — Crimson Nylium over Ridrock/Netherrack, Crimson Trees, Diabolum, Infernum, Cinnabind, Bonfire Lotus, and Crimson Turf; pools are Lava. Zombie Pigmen roam here.
• Azure Forest — Basalt Azure Nylium with Azure Trees, Azzurum/Inverted Azzurum crystals, Spineapple, and Luminescent Nettloid; built on Basalt over Ridrock with Gravel veins.
• Ebony Forest — Basalt Ebony Nylium over Obsidian, Ebony Trees, Bulb Vera, Plorumpora, Stellar Starflower, and Milky Way Thistle; its fluid is corrosive Acid.
• Basalt Deltas — Basalt and Scoria terrain with Brimstone stalagmites/stalactites, Craggy Spikes, Magma flows, Creeping Malice vines, Fierofern/Fierofolha, and Magmoss.
• Soul Sand Valley — Soul Sand and Soul Sandstone with Fossils, Spinal Columns, Dry Ribs, Anecrome (Soulflower), and Jet Crystal clusters. The danger biome: it spawns both Skeletons and Wither Skeletons in large numbers.
• Crystal Caverns and Great Cysts — deep cave biomes; the Cysts flood with Sanguis.

Nether dungeons

Buried in the deepest part of the Nether (generated around chunk-y -10, beneath the forests) are multi-room dungeons assembled from entrance rooms, semirooms, bridges, libraries, altars, and secret rooms. There are four types, each with its own theme, pillar block, and mob roster:

Their placement is sparse (a probability roll per 4×4 chunk region), so they take searching to find — and several Nether achievements (entering the Nether, reaching the Sky, and progressing through locked dungeon doors) reward the trip.