Structural OG - Realistic Building Physics & Structural Integrity

Forge • NeoForge • Fabric • Quilt | 1.12.2 → 26.3

Build it right or watch it fall. Structural OG brings realistic building to Minecraft without turning you into an architect. Every block you place has to be held up: support starts at the ground and fades a little with every block it passes through. Walls and pillars carry weight well, but reaching out sideways costs a lot. Put Foundations under your walls, lay wooden or steel beams under wide floors and bridges, and your builds stand. Skip them, and roofs crack, creak and come down.

Every player gets the Builder's Guide book the first time they join, with all the rules in a few short pages.

The scaffolding goes, and a roof that only the scaffolding was holding comes down with it.

• 🌍 Support starts at the ground. Rock (stone, deepslate, any solid block that was already there) gives 100%. Soft ground (dirt, grass, sand, gravel, snow, mud) only gives 60%, so tall walls and wide roofs on it fail.
• 🧱 Foundations fix that: put them under your walls and pillars and they give 100% on any ground.
• ⬆️ Stacking costs little. A wall or a pillar loses only a few points per block, so towers are fine.
• ➡️ Reaching out costs a lot. Overhangs, balconies, floors and flat roofs lose much more per block. How far you can go depends on the material (see below).
• 🏠 Roofs and ceilings work like you'd expect. Stairs and blocks laid diagonally on each other hold like a sloped roof, and blocks can hang under a ceiling.
• 🪜 Scaffolding holds anything while it stands. Build with it, then take it down at the end: if the structure was badly made, it comes down too.
• 💥 Collapses are real. A block left without support cracks, creaks and falls half a second later as a falling block. It hurts whoever is under it, and what it leaves behind is checked again, so a collapse can spread. Blocks with an inventory, doors and beds break and drop instead of falling.
• 🛡️ Your world is safe. Only blocks placed by players obey the physics. Natural terrain, caves, trees, villages and other generated structures, and everything you built before installing the mod, never fall.

Out from an old wall, plank by plank: the level in the off hand shows the cracks getting deeper, and the sixth plank falls.

Material	Loses going up	Loses going sideways	Longest overhang from the ground
Glass, wool, leaves, dirt, sand...	6	40	2
Stone, bricks, deepslate, terracotta...	2	25	3
Wood (planks, logs, fences, stairs...)	3	18	5
Concrete	1	15	6
Wooden Beam	2	10	9
Iron, copper, gold, chains, bars...	1	8	12
Steel Beam	1	5	19

Blocks laid on top of a beam rest on it, so a beam under a floor lets the whole floor reach much further. Modded blocks are sorted by the words in their name (and their sound), so they work too. Every number can be changed in the config.

Builder's Level: hold it (in either hand) and look at a block. The bar above your hotbar shows its support (green, yellow or red), its material and how much it loses up and sideways. Blocks around it that carry a heavy load show cracks: the deeper the cracks, the closer to falling. Look at the ground and it tells you whether it's solid or soft.

Builder's Guide: a written book with the rules, given to every player once, the first time they join. It's translated (English and Spanish). Lost it? Right-click a Foundation with a plain book and you get a new one.

A block placed close to its limit also cracks for a few seconds as a warning, even without the level.

Foundation (8): cobblestone and gravel in a checker pattern.

Wooden Beam (3): three logs of any wood in a row.

Steel Beam (4): seven iron ingots in the shape of an I.

Builder's Level: a glass block between two planks.

You'll find the blocks in the Building Blocks tab and the level in Tools & Utilities in creative.

Everything can be changed in config/structuralog.properties (created on the first start, with a comment on each line):

Setting	Default	What it does
enabled	true	Turn the physics on or off
creativeBuilds	true	Blocks placed in creative mode obey the physics too
softGround	60	Support given by soft ground (Foundations and rock give 100)
collapseDelay	8	Ticks a block cracks before it falls
collapseDamage	true	Falling blocks of a collapse hurt like an anvil
warnings	true	A block placed close to its limit cracks for a moment
giveGuideBook	true	Give the Builder's Guide to every player on their first join
loss.*	see the table	How much each material loses going up / sideways
words.*		Which blocks are which material, by words in their id
ignoredBlocks		Blocks that never fall and never hold anything up
ignoredDimensions		Dimensions without physics (e.g. minecraft:the_end)

Loader	Minecraft versions
NeoForge	1.20.4, 1.20.6, 1.21.1, 1.21.3, 1.21.4, 1.21.5, 1.21.8, 1.21.10, 1.21.11, 26.1.2, 26.2, 26.3
Forge	1.12.2, 1.16.5, 1.17.1, 1.18.2, 1.19.2, 1.19.3, 1.19.4, 1.20.1, 1.20.2, 1.20.4, 1.20.6, 1.21.1, 1.21.3, 1.21.4, 1.21.5, 1.21.8, 1.21.10, 1.21.11, 26.1.2, 26.2, 26.3
Fabric / Quilt	1.16.5, 1.17.1, 1.18.2, 1.19.2, 1.19.3, 1.19.4, 1.20.1, 1.20.2, 1.20.4, 1.20.6, 1.21.1, 1.21.3, 1.21.4, 1.21.5, 1.21.8, 1.21.10, 1.21.11, 26.1.2, 26.2, 26.3 (needs Fabric API)

• Requires OG Core (the small library all OG mods share).
• Install it on the client and the server: it adds blocks, so both sides need it. In single player just add it to your mods.
• The physics run on the server only, a few changed blocks at a time, so big bases don't lag. Which blocks you placed is saved in the world's data folder.
• Works with Sodium, Iris and shader packs (the screenshots use Complementary Reimagined).
• Tested in-game on every loader, from the oldest to the newest version: overhangs of wood from rock, from a pillar on grass and from one on a Foundation, both beams, a bridge that loses one end, scaffolding taken down under a floor, a block in mid-air, a sloped roof, a support blown away without a player, the level and the guide. Tested on a dedicated server too.
• MIT License: use it in any modpack.

More screenshots in the Gallery tab.

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💬 Found a bug or have an idea? Leave a comment. Feedback is always welcome!

⭐ If Structural OG made your builds feel real, a follow helps a lot!

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