I don’t know why, but somehow, the center of the mesh I was working on randomly moved a little bit to the right. Now, it’s at the point where I can’t sculpt symmetrically. How can I fix this?
Transform -> S. Pivot
I’ll assume ZB3.5, but it would be helpful to state which version you were working with.
In 3.5 “Local Transformations” is on by default. When active, the mesh will pivot around the last point of contact initiated (where you start the stroke) on the mesh.
If Off (button on the right side of the viewport), the mesh will rotate around its global center (even if partially hidden, the hidden geometry will factor in).
If the “Align to Object button” in the Draw palette is pressed, the object will pivot on the center of any visible geometry.
Local Transformations Off, with “Align to Object” On, would be default ZB 3.1 behavior.
Oops, I think I misunderstood your question. If so, Kerwin is right, you can manually recenter a mesh with set pivot. If your symmetry has become broken, you can repair it with Smart Resym in the deformation palette.