Axiom for Minecraft: get started with the builder's editor

Axiom turns Creative mode into a building editor. Builder Mode adds quick tools in a 10th hotbar slot and a context menu on Left Alt; Editor Mode, on Right Shift, opens a 3D view with selections, fills, brushes and shapes. It is a Fabric mod for Java Edition. Axiom's own menus are in English, so they are named here as they appear.

1. Install Fabric Loader for your Minecraft version, as shown in how to install Fabric.
2. Download Axiom and Fabric API for the same version from their official pages, and put both files in the mods folder.
3. Start the game with the Fabric profile. By installing Axiom you accept its license agreement (EULA), linked on its official page. The first time, Axiom shows a short introduction.

Axiom does not run on Forge or NeoForge, and its page warns that it breaks with OptiFine. Leave OptiFine out of this instance.

Create a world in Creative mode, with Allow Cheats on. A 10th slot with Axiom's icon appears to the right of your hotbar. If it is missing, type /whynoaxiom: Axiom says what is wrong and how to fix it. In single player, /axiomenablecheats turns cheats on in a world created without them.

Press 0 to select the 10th slot, then hold Left Alt and scroll to pick a tool: Move, Clone, Stack, Smear, Extrude, Erase or Setup Symmetry.

• Select: left-click the first corner and right-click the second. Middle-click a face to push that side of the box out, handy around a tree.
• Move or copy: scroll to nudge the selection one block at a time. Scrolling up pushes it away from you. Hold X, Y or Z to stay on one axis.
• Turn it: Ctrl + R rotates it clockwise, Ctrl + F flips it.
• Confirm: right-click. With Clone, keep scrolling and confirming to lay several copies, then left-click to finish.

Stack works the same way, but scrolling adds copies in a row. Size and offset show above the hotbar while you work.

Pick a normal hotbar slot and hold Left Alt. The context menu shows the capabilities on the left (green when on), a hotbar swapper in the middle and a flight speed slider on the right, up to 999%.

• Replace Mode (key R): clicking a block swaps it for the one in your hand, without breaking it first.
• Infinite Reach and Angel Placement: place blocks from any distance and in mid-air.
• Tinker: right-click with an empty hand to change a block's state, for example a stair into a slab or a wall's connections.
• Bulldozer, Fast Place, No Updates, Force Place, No Clip: faster breaking and placing, no block updates, no placement rules, flying through walls.

Ctrl + C while looking at a block copies it with its exact state, ready to place.

Press Right Shift. The game turns into an editor with windows and a toolbar. If your keyboard has no Right Shift, change the key in Options, Controls, Key Binds, in the Axiom section.

• Hold the left mouse button to turn the camera, Ctrl + left button to orbit around a point, Ctrl + right button to pan.
• The right mouse button uses the current tool.
• Middle-click a block to make it your Active Block, the block most tools build with.

Press B for Box Select and drag between two points with the right mouse button; the gizmo arrows resize the box. Press M for Magic Select: one click selects all touching blocks of the same type, such as a whole roof.

• Ctrl + F fills the selection with your Active Block, Ctrl + R replaces blocks inside it, Delete clears it.
• Ctrl + C copies and Ctrl + V pastes a preview: move it with the gizmo, Ctrl + R rotates it, Enter places it.
• Ctrl + J duplicates the selection, and Ctrl + P saves the copy as a Blueprint to reuse in any world.

Press P for the Painter and hold the right mouse button over the terrain: it repaints blocks with your Active Block and, by default, only touches solid blocks, never the air. Ctrl + middle button changes the brush size. The Shape tool places spheres, cylinders, cones, pyramids and more, solid or Hollow, which you move and turn with the gizmo before placing.

Press U for Smooth to round off rough terrain. Every tool has its options in the Tool Options window.

Ctrl + Z undoes the last Axiom action and Ctrl + Y redoes it, in Builder and Editor Mode. The History window lists every change with its block count. A few actions cannot be undone, such as a block swapped with Replace Mode, and the history is wiped when you leave the world, so save a copy of the world before big edits.