X mirror & Topology mirror don't work

Support Modeling
1

I have a mesh with an armature modifier on it, but when I go into edit mode X mirror and Topology mirror don’t work.
Is it because my mesh has an armature modifier?
Thank in advance.

2

My experience with X-mirror has been than it tends to stop working and I cannot tell why. I just added an armature to the default cube and X-mirror kept working so I don’t think that your armature itself is the root cause.

3

In attachment I send a .blend file.
I made the following steps:

  1. in edit mode I moved the default cube.
  2. I created the armature
  3. I selected the cube then the armature and parented with automatic weights
  4. I added a mirror modifier to the cube and applied it

Attachments

X-mirror.blend (474 KB)

4

If Topology mirror is not selected everything works well, what is the use of topology mirror?

5

If the shape of the mesh is asymmetrical, but the topology is still symmetrical, you can still mirror left & right.

example: add a monkey head. Select some vertices on ONLY 1 side and move them a bit. Enable X Mirror & Topology Mirror & move those vertices again. The vertices on the other side will snap to the same mirror location. X Mirror alone won’t do that

6

Is the topology of the cube object in the file X-mirror.blend not symmetrical?

7

I see what you mean. So the question is why does it work on Suzanne head and not a default cube. The tool description does mention “matching unique topology”, but I have no idea how ‘unique’ it should be.

Changing the cube a bit (creating differences in sides & front & side), copy these changes to the other side, and it actually starts working.