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How to use the Mirror Modifier in Blender

Written by Hayden Falzon author image Hayden Falzon

Published on Updated on
Reading time: 4 mins

The Mirror modifier is a modifier within Blender. It can be added to most objects capable of using modifiers, by navigating to the modifier menu and adding the mirror modifier. When added, it will mirror your object across one or multiple selected axis.

By default the modifier will use the object's origin - so if you are seeing any problems - be sure to apply your objects scale and rotation. Also ensure that your origin is centered in the position where you wish the modifier to mirror from.

What is the Mirror Modifier

The Mirror modifier in Blender allows you to mirror a mesh along its local X, Y, and/or Z axes, effectively duplicating one side of the object to create a symmetrical counterpart.

This tool is particularly useful for modeling symmetrical objects, characters, and architectural elements. Additionally, the Mirror modifier can utilize another object as the center of mirroring, using its local axes instead of the modified object's axes.

Options in the Mirror Modifier

Example of the the mirror modifier

The Mirror modifier offers several essential options to control the mirroring process:

  1. Axis Selection

Choose one or more axes (X, Y, or Z) along which you want to mirror the mesh. Each axis selected will generate additional mirrored copies of the object.

For instance, selecting the X axis will create a mirrored version of the original mesh with negative X values.

  1. Bisect and Flip

If the mesh is already on both sides of the mirror plane, enabling Bisect will cut the mesh along the plane, keeping only one side to perform the mirroring.

Flip allows you to switch the side kept and mirrored when Bisect is enabled.

  1. Mirror Object

You can use an external object (usually an empty) as the mirror center, using its position and rotation to define the mirror planes.

Animating this object allows you to dynamically move the mirror axis.

  1. Clipping and Merge

Clipping prevents vertices from moving through the mirror plane during transformations in Edit Mode.

Merge ensures that vertices within the Merge Distance will be merged with their mirrored counterparts.

  1. UV Mapping

The Mirror modifier can also mirror UV texture coordinates across the middle of the image.

UV Offsets allow you to shift mirrored UVs on the U/V axes to avoid overlapping and artifacts in baked maps.

  1. Vertex Groups

The modifier can attempt to mirror existing vertex groups following the left/right naming pattern (e.g., ".L" and ".R").

A mirror side vertex group must already exist and be completely empty.

Practical Usage Scenarios

The Mirror modifier is a versatile tool that finds applications in various scenarios, including:

Character Modeling: Create symmetrical characters and creatures with ease, modeling one side and letting the Mirror modifier handle the other.

Architectural Design: Design architectural elements with perfect symmetry, such as buildings, structures, and interiors.

Hard Surface Modelling: Achieve precision in hard surface modelling, ensuring uniformity and symmetry in complex designs.

Tips for Accurate Positioning of the Mirror Plane

To apply the Mirror modifier accurately, follow these steps for precise positioning of the mirror plane:

Select the edge or face that will serve as the axis of mirroring.

Snap the 3D Cursor to the selection.

Use the Set Origin menu to set the origin of the object to the 3D Cursor's location.

Alternatively, use an empty as a Mirror Object and move it to the correct position for mirroring.

Conclusion

The Mirror modifier in Blender is a valuable tool that empowers 3D artists to achieve perfect symmetry in their models efficiently. Whether you're creating characters, architectural elements, or intricate designs, the Mirror modifier simplifies the modeling process and ensures accuracy in your creations.

Experiment with the different options available in the Mirror modifier to explore a wide range of design possibilities. From characters with flawless symmetry to architectural designs with precision, the Mirror modifier in Blender is an indispensable tool for any 3D artist seeking to elevate their work to new heights.

Author Avatar

Hayden will tell everyone that he is not a programmer, game developer, educator, artist, 3D modeller or animator... instead, he tells people he is a storyteller.

Graduated from the Australian Film Television and Radio School (AFTRS) Bachelor, Hayden has been proactive in fostering a multidisciplinary outlook on digital storytelling across all of its mediums.