Symmetry

Symmetry Mode allows rapid automatic mirrored building of a ship. The mode displays as a translucent plane in either red, green, or blue, according to the coordinate plane being used for mirroring.

Note: Symmetry Mode is only available in Creative Mode.

Which Mirror Planes exist

Symmetry Mode cycles through 7 mirror modes:

• center-of-red-plane, edge-of-red-plane,
• center-of-green-plane, edge-of-green-plane,
• center-of-blue-plane, edge-of-blue-plane,
• Block Placement Mode (default)

The regular plane runs through the centre of a row of blocks, while the offset plane runs along the edge of blocks.

One, two, or all three planes may be activated at once, but only one of each type (either regular or offset) can be active for each plane.

How to Activate Mirror Planes

This diagram shows how you cycle through symmetry mode states

To select which plane is mirrored:

1. Have a block ready to place and face the ship.
2. Activate Symmetry Mode by pressing the Toggle Symmetry hotkey N key.
3. Press the Cycle Symmetry Mode hotkey M key multiple times to cycle through the axes until you see to the plane that you want to mirror. For each active mirror plane, you can choose either regular or offset.
4. Aim at the location where you want to set the mirror point, and -click to activate the plane.
5. Repeat steps 3 through 5 if you want to mirror along more than one plane.
6. Press the Cycle Symmetry Mode hotkey M key until you are back in Block Placement Mode.
   In Block Placement Mode, only the mirror planes that you activated are now visible, and the ghost preview of the block that you have ready to place is now shown mirrored on the ship.

Now you can click to place or click to delete mirrored block(s).

How to Deactivate Mirror Planes

To remove a symmetry plane, repeat the steps above.

1. Use the Cycle Symmetry Mode hotkey M key until you get to the active plane that you want to deactivate.
2. click anywhere on the ship to deactivate this plane.
3. Cycle back to block placement mode.

How to Toggle Symmetry Mode

The planes being set alone does not activate symmetry mode.

• To use symmetry mode while building a ship, turn it on by pressing the Toggle Symmetry hotkey N key.
• Press the same hot key to turn it off again.

Toggling is useful to control on the spot which of your clicks shall be mirrored and which not.

Once the planes are in place, and you are back in block placement mode, and symmetry mode is active, the game attempts to mirror all block placement on the opposing quadrants of the planes. To be successful, there must be enough free space and a neighbouring block for the mirrored block to attach to in the opposing quadrants.

All active planes are used for mirroring when symmetry mode is active:

• If 1 plane is active, two blocks are placed.
• If 2 planes are active, four blocks are placed.
• If 3 planes are active, eight blocks are placed.

How to build symmetrical subgrids

Subgrids are the parts of your build that are attached through Mechanical Blocks such as Rotors. When you build complex subgrids with mirror symmetry (such as two rotated nacelles or walker legs or twin custom turrets) using Symmetry would be handy — but Symmetry does not work across subgrids.

In this case, use the following workaround (credit to community member BlackArmor):

1. Build a stalk of temporary armour blocks out from the start of the first subgrid, away from the main grid, to where you have free space.
2. Then set a mirror plane in the middle of the stalk.
3. While you now continue building the first subgrid, a copy will be mirrored on the other end of the stalk.
4. When you're done with the first subgrid, remove the stalk and cut both subgrid copies free.
5. Finally, use CTRL key+X key to cut the floating mirror copy, and then CTRL key+V key to paste it onto its own rotor on its own side of the main grid, where you actually wanted it.

How to use Symmetry mode to mirror subgrids (by BlackArmor)

What are caveats of symmetry mode

Be careful when deleting blocks in Symmetry Mode. It’s possible that the mirrored quadrants are not 100% identical — perhaps because you had forgotten to switch on Symmetry Mode for a few clicks, or because a stray loosely floating block prevented a mirrored block from being placed. Even if deleting the block did not split the grid in the quadrant that you were working on, the grid could split in one of the (accidentally different) mirrored quadrants. For larger builds, remember to check the other quadrants regularly and clean up obstacles such as floating blocks.

For tips how to fix split grids, see Merge Block.

If you are copying station blocks with symmetry planes attached to them and paste them together, multiple sets of the same planes will show for the same station. However, the planes are only active for their original blocks.

References

• How to use mirroring in Space Engineers by Maxiusslight