Symmetry tool does not work properly after some use

[k014]

brief explanation: I usually play medium for about 2 hour sessions, but after 30 min, the symmetry tool starts to stop being symmetric at all, and I have to redo some parts, is like the place off-centers a little bit from the starting position.

this make modelling really frustrating, I have been trying to replicate this issue but it only happens after a long session of modeling, and then you notice the symmetry plan is no longer in the center of your model.

anybody have experienced this issue?, again I dont know how to replicate it, but I have uploaded a long video where this happened to me, here it is:

https://www.twitch.tv/k014/v/106937759

some (not all) time codes when I realize the symmetry plane is off center:
1:21:00
1:22:38 // Here I realized that after fixing the nose because the symmetry was off center, 
1:48:18 // symmetry plane again moved (or the model moved)

Has anybody experienced this too?

EDIT: somebody mentioned that this is caused because I move layers in layer mode, but this is not the case, I did not use layers at all, and I did not move the symmetry layer at all

[P3nT4gR4m]

If you move a layer in normal mode the symmetry plane moves too. If you move it in layers mode, tho (holding down the left stick) the layer moves independently of the symmetry plane. This has caught me out a few times.

[nalex66]

P3nT4gR4m said:

If you move a layer in normal mode the symmetry plane moves too. If you move it in layers mode, tho (holding down the left stick) the layer moves independently of the symmetry plane. This has caught me out a few times.

Yeah, this has bitten me too. It would be nice if each layer had its own symmetry plane that stayed with it, or at least an option to create a "local" plane for the layer.

[TrancerSpacey]

@k014: I wanted to post exactly the same issue. There is some minor offset in the layers, suddenly things who should fit together don't exactly fit together anymore. When you want to erase some minor details on the one side, it has no effect or to much effect on the other side. It is very frustrating.

Because you can't place the object precisely manually to recenter it, because there is no "snap to grid", "snap to symmetry plane" or something like this and recentering has no effect. I'm working on a very complex sculpt at the moment and it drives me crazy!

[P3nT4gR4m]

nalex66 said:

P3nT4gR4m said:

If you move a layer in normal mode the symmetry plane moves too. If you move it in layers mode, tho (holding down the left stick) the layer moves independently of the symmetry plane. This has caught me out a few times.

Yeah, this has bitten me too. It would be nice if each layer had its own symmetry plane that stayed with it, or at least an option to create a "local" plane for the layer.

I can just about live with global symmetry, for time time being. I agree that, long term, local would definitely be preferable but I'd really like to be able to positionally lock individual layers so this doesn't happen. It's too easy to shift the wrong layer, accidentally and not notice til it's too late.

This actually happened to me last night and I got round it with an old Blender trick - slice the object in half, dump one half and then duplicate and flip the remaining one. Because it flips across the mirror plane, you have to line your half-object up with that first then it's just a case of smoothing out the seam and you're back on track. 

[nickzucc]

I have had the flip or mirror flip about the objects center and not by the world center, I then had to move it into position by hand. I'm not sure what I did wrong in those cases, because I checked the symmetry plane and it was where I expected. Is this happening to anyone else?

[nalex66]

Yeah, I've noticed this too--everything mirrors about a global symmetry plane except the Flip tool, which seems to use a plane local to the object.

I was doing eyes for my latest sculpt, and I wanted to adjust their position. I thought this would be a perfect time to use @P3nT4gR4m's above-described trick of delete/duplicate/flip. I deleted one eye, repositioned the other, and duped and flipped. Unfortunately, the new eye was off to the side, half way out of the head!

It's weird, because if I continue to do mirrored sculpting after moving a layer, it still respects global symmetry, rather than the symmetry plane used for the Flip command. 

[ChrisTron]

I also noticed that relative position between the layers changes slightly while using Medium. That becomes really annoying if you use the layers to differ between materials (e. g. metal and luminous). You thoroughly place all the effects and after two or three minutes they are slightly off center. I had to distribute all the various parts (body, hands, gloves, joints) of this sculpt to different layers so I could rearrange them individually every 15 minutes. If the different parts a far away from each other you never get them aligned perfectly again. Plus the loss of symmetry it was an awful lot of work just to get it right for the photo shoot.

[Sankam]

This happened to me after only about an hour of sculpting.  I was working on a single layer, never went to the layer palette or the environment setting.  The center drifted perpendicular to the symmetry plane and continued to drift as I continued to work.  I think a Lock to Plane movement function for the geometry-- or even a single-axis movement solution-- might help with this sort of thing, or to line up geometry on a different layer that has to be moved.  It's so frustrating to try and re-align the symmetry plane that I feel like it's easier to just start over.  Feels bad either way.

[Sankam]

Update: There is a way to save the position of the Symmetry plane.  In Scene mode (Yellow landscape button), select the symmetry plane and then select Options (the green cog button).  This brings up a palette with options for saving the position of the plane and restoring it to the saved position.  

There is also an option for centering geometry there but I don't know if it works correctly-- my model ended up upside-down to my side when I tried it, but I had been sculpting for some time so I may have started off upside-down without realizing.

Unfortunately for my current sculpt, the plane drifts noticeably within about five minutes, but in a fresh file the plane seems to be properly fixed in space.  I'm going to try importing the geometry of the current sculpt into a fresh file and see if that works.