The main gameplay in Space Engineers is building functional structures such as space ships, drones, rovers, trucks, factories, mechas, space stations, planetary bases, and so on; these structures are called "Grids". Grids are made of blocks, blocks are made of components, components are made of materials, materials are made of ores.
This page is an overview of basic game concepts such as block placement, welding and grinding, mobile versus static, large versus small, and the minimum requirements such as power.
Tip: If you already know all the basics from this page, continue with the checklist of further game knowledge at Building Tips!
Are There Requirements Before I can Build?[]
In Survival Mode you must have components (such as 
Steel Plates) in your inventory before you are able to place a block; the components are used up over time.
In Creative Mode you can place all blocks "for free". If you want to practice building, it's recommended to start a custom "Planet Earth" game in creative mode.
Placing Blocks[]
Building in Space Engineers means that you place blocks in the world:
- First select a Block (such as a
Light Armor Block) from the Toolbar by pressing a number key from 1-9 on the keyboard. - Then LMB click in the world to place the block frame.
- Making placed block frames functional is called welding.
- Dismantling and salvaging blocks is called grinding.
The Toolbar contains handheld tools in slots 1-3, then a light armor block in slot 4, and then other common blocks.
When your space engineer is holding a selected block from the Toolbar, you have entered Block Placement Mode. Holding a block is a prerequisite for certain keybindings to work, such as block rotation or texture painting.
Press (G key) to configure your toolbar by adding the blocks you want to build with. When the G-Menu is open, you can also hover the mouse over the Toolbar to read tooltips to identify a block or action. For details, read Toolbar.
Interacting With Built Blocks[]
When you aim (target and hover) the crosshairs over certain areas of certain blocks, a yellow highlight appears. You commonly interact with buttons, doors, cockpits, cargo access ports, terminal keypads, etc. by aiming at the interactive area and clicking, or pressing a key such as (F key).
You cannot interact with unfinished (unwelded) block frames.
What is a Grid?[]
A spaceship, a rover, a base -- any structure built out of connected blocks that touch each other is called a grid.
Large Grid, Small Grid[]
A grid can be either large (think: space station sized) or small (think: car sized). In game terms, a structure is built out of either only large grid or only small grid blocks. Some blocks only exist in large-grid size, or only in small-grid size, most exist in either size. (For more complex cases, read about multigrids and subgrids.)
Important: Press the same toolbar slot number again to toggle a selected block between large or small size before placing the block!
Static Grid, Mobile Grid[]
A grid is either static or mobile:
Examples of static grids are:
- bases on planets,
- bases on asteroids,
- stationary cranes,
- space stations (they don’t orbit).
Examples of mobile grids are:
- spaceships (any grids with thrusters),
- race cars, trucks, and rovers (any grids with wheels),
- Mechas (mobile grids that walk using Mechanical Blocks such as rotors),
- mobile utility machines (miners, fork lifts, constructors, salvagers, mobile cranes),
... and what ever else you can think of!
Using the Info Screen, it is possible to convert grids between static and mobile under specific conditions. On this screen, you can also see useful info about the grid and name it.
What does welding mean?[]
When you place blocks in Creative Mode, they will appear fully built ("welded") in the world.
In Survival Mode, placed blocks appear as unwelded frames.
- Unwelded frames already have the mass and solidity of the finished blocks, and they already carry electricity.
- Unwelded landing gears are already magnetic.
- Unwelded frames have almost no hitpoints, which makes them quick and cheap to build, but very fragile when hit by one stray bullet or collisions.
- Unwelded functional blocks will not have any functionality, and they use no power.
- Unwelded conveyors and ports do not extend the conveyor system.
In Survival Mode, to benefit from the full functionality and hitpoints of a placed block, you must weld the block:
- You either need to have components in your player inventory and use a hand-held welder on the block.
- Or you must have components in a utility ship's conveyor system and use a conveyored ship-based welder on the block. The ship-based welder is faster and has a wider range than the engineer's hand-held welder.
Point the hand-held welder at a block to get a HUD display listing required and missing components. It is recommended to use the Build Planner to keep track of needed components for manual welding.
Who welded a grid determines ownership and is also a factor in hacking.
What does grinding mean?[]
A constructor ship with a grinder and welder attachment.
Grinding a block removes it from the grid and returns the components into your inventory. If your inventory is full, components will be dropped on the ground (or into space), so beware.
Before grinding a block, verify that the block is not the only thing holding two halves of the grid together, so the grid does not break in two (if that happens, see Merge block).
Tip: In Creative Mode in Block Placement Mode, RMB clicking a block deletes it faster than grinding it would.
Basic Building Rules[]
A rotated Conveyor Junction with visible conveyor ports
Choose between mobile or static Grid[]
The placement of the first block determines whether it will be a mobile or static grid.
To start building a static grid:
- Select any large-grid block from the Toolbar, such as a Light Armor Block.
- The first block placed must intersect with voxels, such as asteroids or planets.
To start building a mobile grid:
- Select either a large- or small-grid Landing Gear from the toolbar and place it as first block.
- No blocks of a mobile grid intersect with voxels.
Add Power[]
If you want functional blocks to work (and not just use them as decorations), add Power blocks.
- All touching blocks of a grid carry electricity, no cables are needed.
- Note that Hydrogen thrusters require a small amount of power to get the Hydrogen fuel from tanks through conveyor ports.
Transport Items Through Conveyor Tubes[]
Build a conveyor system to facilitate the transport of items and gases between functional blocks. Conveyors are useful if you need to move:
- Ores from drills into refineries,
- Materials from refineries into assemblers,
- Components from assemblers into Welders,
- Ammunition into turrets,
- Hydrogen and Oxygen gasses and Ice into generators or from/to tanks,
... or any items into any cargo containers.
Tip: Conveyors also give you the ability to drag and drop Items on the inventory screen!
Blocks with conveyor access have visible yellow ports. Keep an eye on where the ports are when placing functional blocks: To link blocks into the conveyor system, either place them so that their ports touch, or connect the ports with conveyor tubes.
Make a grid mobile[]
The following blocks are required to make grids properly mobile:
- To be able to turn (yaw left and right), or to level (pitch up or down) a mobile grid by moving the mouse, add two or more gyroscopes.
- To control a mobile grid, add a cockpit block (or a Remote Control).
- To be able to accelerate and steer a mobile grid using the WASD keys, add one of the following mobility block types:
- Either thrusters in all six directions,
- or several wheels with a wide wheelbase for stability,
- or mechanical legs with a wide stance for stability.
Is there an undo command?[]
There is no built-in undo command in a physics simulation where objects can be in motion at any time. Instead, you save often, and reload when there’s need to revert to the previously saved state.
- Quick-save the game by pressing 'Shift+F5'.
- Then you can quick-reload by pressing 'F5' (undo/revert).
If you are at a stage when building where you undo a lot, and you want full manual control about what is being saved, temporarily switch off Auto-Save in the World Settings.
See also: Klime‘s “Undo” mod on the Steam Workshop
Creative Mode Keybinds[]
In Creative Mode, with a block selected from the toolbar, you can ctrl+drag the mouse to place several of the same bocks.
You can use ctrl+C to copy the targeted grid into the clipboard, including its inventory. Then optionally rotate the ghost preview into position, and paste it with ctrl+V. If you align the ghost preview with an existing grid, they automatically merge into a single grid when pasted.
You can use ctrl-X to cut the targeted grid. Cutting means, you keep a copy in the clipboard and delete the grid from the world. The next grid you copy or cut will replace the contents of the clipboard, so don’t forget to paste the copy if you don’t want to lose it.
See also Key Bindings.
Videos: How to build[]
The best way to learn the process of building is to watch the included videos (press F1 in game); then watch tutorial videos and streams shared by the Space Engineers community, such as Splitsie’s videos.