ZBrushCentral

mesh center / world coordinates

ZBrush Usage Questions
#1

hello,

I occasionally have problem with case concerning mesh center or world center, it somehow get me sometimes confused.
how does zbrush calculate it ? or how to reset it for good for one subtool.

The only way I have found to repair it is “mirror and weld” but it’s not always working.
should I use “unify” first to mesh be reset to world scale ? then mirror and weld ? or if I unlock pivot and move it and then put it manually in center will do the case ? well not entirely.

Could someone share tips about world / tool geometry fixes or other ways ?

#2

By default, ZB calculates symmetry based on the center of the selected tool. If you activate local symmetry, (L.sym) it calculates center based on the selected subtool or visible mesh portion, but it still requires that mesh to be symmetrical along one local axis or another. If the subtool is rotated non-symmetrically in the world space, symmetry will fail. In other words, perform your symmetrical operations before posing a mesh–though Transform > Poseable symmetry can be of use in some situations if your topology is symmetrical.

As far as Mirror and weld, it only works in one direction along the selected axis. So you may first need to “flip” the mesh to the other side via Tool > Deform > Mirror to get the mesh to M&W to the side you want.

#3

yes thank you, but my problem goes little deeper.
I’m working on tool exported from photoscan, the tool/model is now symmetrical thanks to mirror and weld, but somehow it is still not in place in world coordinates and I cannot find the way to make it 0,0,0. Local symmetry yep it works…but still got two glitches where model lost his whole symmetry thing and stopped working properly. After zremeshing also problems ouccured with uneven symmetry.

there is a way that I can tell zbrush that this model is in 0,0,0 this point is axis of symmetry etc ?

#4

You can manually set a pivot point with Transform > S.Pivot, but if symmetry is failing on your mesh, that means it simply isnt symmetrical for one reason or another, in terms of the tool’s worldspace. Sometimes meshes get accidentally pushed out of place. (perspective mode can distort your transformations–switch it off to model with absolute precision)

The symmetry functions in ZB arent magic, but they do perform reliably. If symmetry isn’t working, you need to either M&W to force topological symmetry, or use Tool> Deformation > Smart Resym to mirror form without changing topo (along a symmetrical mesh).

#5

well yeah that’s why when I have cleaned tool from scan I have made “mirror and weld” with half of face and then it became symmetrical. But then with zremeshing something went wrong and want part of the lip was misbehaving and I thought it could be problem with world cords. But it could be as You are saying “accidentally pushed out of place.”

#6

Zremesher responds to active symmetry, and will change its re-meshing based on your settings, assuming the mesh is actually symmetrical. Just FYI.

Also, see my ninja edit above about perspective mode.