Perplexing issue with centering

[CdeV]

Hi Guys,

I have run into a strange situation with the location of my model again and it is unclear to me how to resolve it. I am hoping someone can shed some light here.

My body model seems to be centered. I had an issue with previously (http://www.zbrushcentral.com/showthread.php?195670-how-to-re-center-a-model-that-has-gone-slightly-off-center) but I resolved it. When I sculpt with X symmetry on the body the center point is right where it should be, and when I show the Grid the model is clearly centered in relation to that.

I just designed a crown to go on the figure. I made it in Rhino and when it is Rhino it is centered. But when I import the crown to zbrush it is slightly off center when compared to the body and the Zbrush Grid and the X symmetry. You can see in the image below how the crown is slightly to the left of the head. If I export the body from Zbrush and import the body into Rhino, the body is slightly off-center.

So I am confused because in Zbrush the body is on-center but the crown is off-center, but in Rhino the crown is on-center but the body is off-center!!

To make matters more confusing - when I import the crown model into a clean document page in Zbrush (by choosing any polymesh 3D tool and then importing the .obj) the model is indeed centered. It is only when I import the model into the document I am working on with the body that the crown is off-center.

Is there anyone out there who may be able to offer an explanation here and/or a way of correcting the problem? Please see images:

Zbrush - body on-center, crown off-center

Rhino - crown on-center, body off-center

Zbrush, when I open the crown in a separate new document it is on center

Attachments

[Thor]

If it’s centered in a “new document”, you should be able to just append it as a new subtool to your body subtool. It should stay in the same position (I always do my importing like this - I never use Import with Add)
You can also verify the position by going to: Tool > Geometry > Modify Topology > Position, and ensure that Xposition is at 0

[CdeV]

Thanks for your reply Thor. The weird thing is that when I import the document into its own document it comes positiion is this:

But then when I append it to the Body file, it’s position is this:

…? I did not change a thing, just appended it. Why is it changing? You are right, I can center it using the Position numbers and make sure it aligns with the body that way, but I want to understand what is happening here, why the values are changing automatically when I append it. There is something I’m not understanding about the way that Zbrush deals with the grid/center/position, can anyone explain?