ZBrushCentral

X-axis symmetry problem

ZBrush Usage Questions
#1

Hello ZBrushCentral and present company.

I have a problem with Zbrush right now. I’m on a Windows 7 64-bit PC running Zbrush 3.1. I am sculpting a human figure, and the x-symmetry function doesn’t mirror equally. I’ve looked through the preferences and menus, and I don’t see any way to control this imbalance. The Transform menu has the symmetry subcategory, where I have Activate Symmetry, >X< and >M< toggled on. There are no alpha channels yet.

Symmetrical deformations DO happen, they’re just sometimes weaker or not there at all.

What am I missing?

mirroring problem.jpg

#2

First off, why are you still using 3.1? That is nearly 4yrs old I think…maybe 3.
4 is a free upgrade for both pc and mac.

Secondly, it appears that your mesh isn’t centered on the X axis, that is why you are seeing uneven deformations on the mirrored side.

You can try to use smart resym on the object, or unify to fix the center point. there are another couple of options as well if those don’t work.

#3

@ goast666

thanks for the help, but that didn’t work for me. Maybe I’m doing it wrong, but I’m still seeing the same effect as before. What are those other methods you mentioned?

I’m doing this for student work and don’t feel that I can continue without fixing it, because it just won’t be mirrored properly. Hopefully I can figure it out before I fall behind. My instructor doesn’t respond to questions that often.

I have 4.0 now, but it’s still the same problem as before. I didn’t know there was an adjustable x-axis. I always thought it was a fixed axis relative to the tool being sculpted. How can it have moved?

#4

Hope this helps.

Find two polygons, one on either side of the axis that you want to be the new sym line. Hide everything but those two (4 in my case). Transform>sPivot. This will move the entire mesh to the center of the world if no symmetry is selected. If you have X selected then it will move that object in X and only X (I think anyway). If you wish to put the mesh back into its starting location then you can use transform>cPivot

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symHelp.jpg
symHelp.jpg1440×1586 281 KB
](javascript:zb_insimg(‘223727’,‘symHelp.jpg’,1,0))

If all else fails you can cut him/her in half, decimate the mesh, export it and mirror the mesh making sure that it is perfectly symmetrical. All of this can also be done in zbrush as well, but I find it easier to deal with sym problems in a traditional 3D app.

#5

thanks goast :smiley: now I understand. Helpful! Is there any way to avoid decimating the mesh if you export and import again? You will lose your Zbrush division levels, except the one you export, right? I know that would’ve worked well with Maya, Duplicate Special to fix the lack of symmetry, but you would lose the detail levels in Zbrush.

If only…

#6

to preserve your mesh you don’t have to decimate it. It all depends on how many points are in your mesh and what your machine and maya can handle.
if you don’t have to decimate the mesh and you can just export half of him then it’s super easy.

cut him in half.
export him
import to maya
mirror him
weld him
export him again.
import to zbrush
tool>geometry>reconstructSubD levels…or whatever that button is called. You can do this as many times as you have all quads to break back down into. Basically you can get all of your subD levels back.

If you have to decimate the mesh to mirror it in Zbrush you can always export out the lowest subD level before you decimate (your base mesh).

Take that into maya and make sure he is symmetrical. Do the above steps with the HP mesh (only decimate it after you cut him in half).

Import back into zbrush after the welding. Import/append the perfectly symmetrical base mesh as well. Divide the LP mesh up to a high poly count (around what you were before you decimated the mesh). Project the details, and do any clean up that is required.

#7

All good information again, thanks Goast. I fiddled with Zbrush to figure out how to cut my mesh in half, and I guess you mean to first ctrl+shift+drag select one half of it? I notice that this works when I export it as an .obj, it comes out exactly as I selected it. If there’s another way, that would be golden, but consider this thread resolved.

Thanks!