The Mirror tool mirrors a selection across a selected axis.
You can also interactively mirror the geometry by holding the MMB and dragging in the desired mirror direction.
Axis of SymmetryпѓЃ
For each transformation orientation, you can choose one of its axes along which the mirroring will occur.
As you can see, the possibilities are infinite and the freedom complete: You can position the pivot point at any location around which we want the mirroring to occur, choose one transformation orientation and then one axis on it.
Pivot PointпѓЃ
Pivot points must be set first. Pivot points will become the center of symmetry. If the widget is turned on it will always show where the pivot point is.
Mirror around the individual origins. пѓЃ
Mesh before mirror. пѓЃ
Mesh after mirrored along X axis. пѓЃ
In Fig. Mirror around the 3D Cursor. the pivot point is the 3D Cursor, the transformation orientation is Local, a.k.a. the object space, and the axis of transformation is X.
Mirror around the 3D Cursor. пѓЃ
Mesh before mirror. пѓЃ
Mesh after mirrored along X axis using the 3D cursor as a pivot point. пѓЃ
Transformation OrientationsпѓЃ
Transformation Orientations are found on the 3D Viewport header, next to the Widget buttons. They decide which coordinate system will rule the mirroring.
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Mirroring in Blender may have multiple meanings. We may want to mirror geometry, or a brush stroke or perhaps we are talking about creating a mirror as a shader. Let’s take a deep dive into mirroring in Blender and see what each of those can mean.
The most common way to mirror in Blender is to use a mirror modifier. We use this to mirror geometry between the positive and negative side of an axis. In object mode, go to the modifier stack and add a mirror modifier to your object. By default, your object will be mirrored on the X axis.
If you are here to find out about how to create a mirror as in a reflective material, click here and I will take you further down the article.
How does the mirror modifier work?
The mirror modifier creates symmetry between the positive and negative part of the axis we mirror across. For example, the geometry we have on the positive side of the X axis can be mirrored to the negative side.
I explain the mirror modifier in this video together with all its features:
But for completion’s sake, I will explain it here in the article as well.
We can start with the new interface in 2.90. The mirror modifier now looks like this. To add it, select your object, go to the wrench tab in the properties panel and add a mirror modifier from the «generators» group.
You can learn more about modifiers here:
I also cover the mirror modifier in this article as part of the most used modifiers in Blender.
The axis settings dictates the axis we will mirror across. Note that we can mirror across one or more axis. Here is an example where we start with 1/8th of a sphere and turn on one axis at a time until we have mirrored the entire sphere around.
In most cases though we only mirror on one axis to create symmetry between a left and right side of an object. But we can also create a complete duplicate in symmetry if we keep the object’s origin in the center.
For example, we can use the mirror modifier to create two or four pillars the exact same distance from the center.
You can learn more about how you can manipulate the origin and pivot point of an object here:
The point we mirror around is the object origin indicated by the yellow dot in the middle, and we mirror in local space. This means that we can move rotate and scale this object and the mirror will follow the object instead of being stuck to the axis of the world orientation.
Apart from the mirror axis we also have bisect and flip settings in the mirror modifier. Where geometry crosses the middle line bisect will cut it off and whatever is left on the other side will get mirrored. The flip toggle will simply flip this around.
Here is an example using the monkey.
Any mesh that cross the local Y axis is simply deleted.
Further down we have the mirror object. This allows us to mirror across another objects coordinate system.
Imagine that I wanted to showcase my mad character modeling skills. In this case I would need some way of mirroring parts of the body across to the other side.
Here I can take the arm and add a mirror modifier to it and set the egg-shaped body as my mirror object.
You can see the origin point of the body is in the middle. This is the point we will mirror across instead of using the origin of the arm that is centered on the arm object.
This is a useful feature for any symmetrical model that we want to divide up into multiple objects.
The clipping setting will make sure that any vertex that cross from the positive side of the axis to the negative side will clip to the 0 position. In essence, we can only have mesh on one side and the mirror on the other side.
This is useful in a lot of cases where we want to model one side of an object that is directly connected to the other side. This way we know that we only have geometry on one side.
The merge setting will merge any vertex that come within the threshold of the 0 line between the positive and negative side of the axis with its mirrored version.
Then we have the data subsection. This portion mostly deal with how we mirror textures. I explain this towards the end of the video above.
In short though, these options allow us to offset any mirrored UV Map and copy over vertex groups to the mirrored side.
Troubleshooting: when the mirror modifier is not working
When starting out using the mirror modifier in Blender there are some things we can check.
The most common problem is that we are mirroring across the wrong axis. It is easy to think that we may mirror from one side to the other of the axis line. For instance, you may think that mirroring on the X(Red) axis would mirror like this:
But this is really mirroring on the Y(Green) axis. We often say that we mirror «across» an axis. But what we really do is mirroring between the positive and the negative side of the same axis.
Another common problem is that we don’t have our origin point in the correct position. We mirror from one side of the origin point to the other. The origin point decides where the positive side of an axis ends and the negative begins if you will.
You can learn more about manipulating the origin point in this article.
The last problem that we will discuss is that we are actually mirroring across the local axis of the object and not the global axis.
By default, our object coordinated are aligned with the world coordinates making them look and behave the same. But if our object is rotated in object mode, the local and global coordinates are no longer the same. This means that we can’t follow the red and green line in our viewport to see where our axis are for the local object. These lines show the global coordinates.
To view the local coordinates I find that it is easiest to first select the local coordinates for our transform orientation and then enable the «move» widget from the gizmo menu in the 3D viewport.
The transform orientation can be found in the middle of the 3D viewport header.
Next we go to the gizmo menu and enable the move widget.
Now we will see the move widget in the 3D viewport with the local axis for our object, and we can set up the mirror modifier according to these coordinates. The arrow is pointing in the positive direction of the axis.
How does the mirror tool work?
While the mirror modifier creates a duplicate on the other side of the axis, the mirror tools flips the object to it’s mirrored version without creating any additional geometry.
The shortcut is Ctrl+M followed by the axis, X, Y or Z that we want to mirror across. If you double tap the axis you will mirror across the local axis instead of the global. We can also find this tool in the Object menu.
This tool also allow us to use different transform pivot points. For example, we can use individual origins for separate objects or separate selections.
We can also use the default median point or the 3D cursor as pivot point just to name a few examples.
How to mirror brush strokes while sculpting?
When we enter sculpt mode, symmetry on the X axis is already turned on by default. This is probably because much of what is sculpted use symmetry. We can access these settings either in the properties panel by going to the «active tool and workspace settings». That is the first tab from the top. Then find the symmetry section and uncheck «X».
We can also find the symmetry settings for mirroring directly in the 3D viewport header while in sculpt mode. Here we can also find the same settings as in the symmetry section by pressing the down arrow to bring up the menu.
Besides mirroring we also have options for tiling and radial. Radial is basically radial mirroring, allowing us to sculpt as many «wings» as we would like.
Here is an example with radial for the Z axis set to 7.
How to create a mirror in Blender?
So what if you found this article and wasn’t interested in mirroring mesh at all, but instead you wanted to create a shader that acted as a mirror? In that case here is a node setup that you can use for both Eevee and Cycles.
In Eevee we also need to add a reflection plane or our mirror won’t reflect anything. We can do this by clicking Shift+A and go to Light probe and find reflection plane.
Align it with the reflective surface and have the arrow point in the direction the plane will be viewed from.
If you want to learn more about shading and the node editor, you can check out this article.
Final thoughts
In this article we took a look at some common ways to use mirroring in Blender. Primarily to create mirrored geometry so that we may save time and don’t have to model everything multiple times as well as getting an exact offset from a middle point.
Mesh Options¶
Sidebar ‣ Tool tab ‣ Options panel
Mirror¶
The Mirror option of the Mesh Options panel allows you to transform vertices symmetrically according to the chosen axis. When you transform an element (vertex, edge or face), if there is its exact axis-mirrored counterpart (in local space),it will be transformed accordingly, through a symmetry along the chosen axis.
Topology Mirror¶
For Topology Mirror to work, at least one of the three Mirror Axis must be enabled.
When using any of the three Mirror Axis options to work on a mirrored Mesh Geometry, the vertices that are mirrored must be perfectly placed. If they are not exactly positioned in their mirror locations then the Mirror Axis will not treat those vertices as mirrored.
Topology Mirror tries to address this problem by determining which vertices are mirrored vertices not only by using their positions but also by looking at how those vertices are related to others in the Mesh Geometry. It looks at the overall topology to determine if particular vertices will be treated as mirrored. The effect of this is that mirrored vertices can be non-symmetrical and yet still be treated as mirrored.
The Topology Mirror functionality will work more reliably on mesh geometry which is more detailed. If you use very simple geometry, for example a Cube or UV Sphere, the Topology Mirror option will often not work.
Example¶
For an example of how to use Topology Mirror open up a new Blender scene, then delete the default cube and add a Monkey object to the 3D View.
Press Tab to put the Monkey object into Edit Mode.
With all the Mirror Axis options disabled move one of the Monkey object’s vertices slightly.
Then Turn the X Axis Mirror on but leave Topology Mirror disabled.
If you now move that vertex again, the X Axis Mirror will not work and the mirrored vertices will not be altered.
If you then enable Topology Mirror and move the same vertices again, then X Axis Mirror should still mirror the other vertex, even though they are not perfectly positioned.
Auto Merge¶
Sidebar ‣ Tool ‣ Options ‣ Auto Merge
When the Auto Merge option is enabled, as soon as a vertex moves closer to another one than the Threshold setting, they are automatically merged. This option affects interactive operations only (tweaks made in the Adjust Last Operation panel are considered interactive too). If the exact spot where a vertex is moved contains more than one vertex, then the merge will be performed between the moved vertex and one of those.
Enables the Auto Merge feature.
Split Edges & Faces
Detects the intersection of each transformed edge, creating a new vertex in place and sectioning the edge and the face if any.
Defines the maximum distance between vertices that are merged by the Auto Merge.
The Mirror tool mirrors a selection across a selected axis.
You can also interactively mirror the geometry by holding the MMB and dragging in the desired mirror direction.
Axis of Symmetry¶
For each transformation orientation, you can choose one of its axes along which the mirroring will occur.
As you can see, the possibilities are infinite and the freedom complete: you can position the pivot point at any location around which we want the mirroring to occur, choose one transformation orientation and then one axis on it.
Pivot Point¶
Pivot points must be set first. Pivot points will become the center of symmetry. If the widget is turned on it will always show where the pivot point is.
Mirror around the individual origins. В¶
Mesh before mirror. В¶
Mesh after mirrored along X axis. В¶
In Fig. Mirror around the 3D Cursor. the pivot point is the 3D Cursor, the transformation orientation is Local, a.k.a. the object space, and the axis of transformation is X.
Mirror around the 3D Cursor. В¶
Mesh before mirror. В¶
Mesh after mirrored along X axis using the 3D cursor as a pivot point. В¶
Transformation Orientations¶
Transformation Orientations are found on the 3D View header, next to the Widget buttons. They decide which coordinate system will rule the mirroring.
Mirror Vertex Group¶
Mesh ‣ Weights ‣ Mirror
Mirrors the vertex group weights. See Mirror Vertex Group for more information.
The X, Y, Z axis along which to mirror, i.e. the axis perpendicular to the mirror plane of symmetry.
To understand how the axis applies to the mirror direction, if you were to mirror on the X axis, the positive X values of the original mesh would become the negative X values on the mirrored side.
You can select more than one of these axes. And will then get more mirrored copies. With one axis you get a single mirror, with two axes four mirrors, and with all three axes eight mirrors.
If the mesh is already on both sides of the mirror plane, it is cut by that plane, and only one side (the “negative” one by default) is kept to perform the mirror process.
When Bisect is enabled on an axis, you can use this setting to switch the side kept and mirrored (i.e. when it is enabled, the “positive” side will be kept, instead of the “negative” one).
An Object Selector to select an object (usually an empty), which position and rotation will be used to define mirror planes (instead of using the ones from the modified object).
You can animate it to move the mirror axis.
Prevents vertices from moving through the mirror plane(s) when you transform them in Edit Mode.
If it is enabled but vertices are beyond the mirror plane and outside of the Merge Distance, the vertices will not be merged. But as soon as the vertices are within Merge Distance they are snapped together and cannot be moved beyond the mirror plane.
Vertices on the mirror plane will be unable to move away from the mirror plane as long as Clipping is enabled. You must disable it to be able to move the vertices along the mirror axis again.
Where a vertex is in the same place (within the Merge Distance) as its mirror it will be merged with the mirrored vertex.
The maximum distance between a vertex and its mirror copy at which they are merged together (being snapped on the mirror plane). Needs Merge to be enabled.
Distance from the bisect plane within which vertices are removed.
DataпѓЃ
With this option you can mirror the UV texture coordinates across the middle of the image.
E.g. if you have a vertex with UV coordinates of (0.3, 0.9), its mirror copy will have UV coordinates of (0.7, 0.1).
Amount to shift mirrored UVs on the U/V axes.
It’s useful for baking (as overlapping UVs can cause artifacts to appear in the baked map), so the UVs can be moved outside the image and not used for baking, but still be used for display.
Try to mirror existing vertex groups, with the following specific prerequisites:
The vertex groups you want to mirror must be named following the usual left/right pattern (i.e. with suffixes like “.R”, “.right”, “.L”, etc.).
The mirror side vertex group must already exist (it will not be created automatically). It must also be completely empty (no vertices assigned to it).
Mirror the texture coordinates around each tile center.
HintsпѓЃ
Many modeling tasks involve creating objects that are symmetrical. This modifier offers a simple and efficient way to do this, with real-time update of the mirror as you edit it. Once your modeling is completed you can either click Apply to make a real version of your mesh, or leave it as-is for future editing.
Accurately Positioning the Mirror PlaneпѓЃ
To apply a Mirror modifier, it is common to have to move the object’s origin onto the edge or face that is to be the axis for mirroring. This can be tricky when attempted visually.
A good technique to achieve an exact position is to select the edge, then snap Cursor to Selection. This will position the 3D Cursor in the center of the edge. Finally, use the Set Origin menu, and select Origin to 3D Cursor. This will move the object’s origin (and thus, the mirror plane) to where the 3D cursor is located, and the mirroring will be exact.
An alternative is to use an empty as a Mirror Object that you move to the correct position.
