Hi !
I made a simple mesh in Blender and and I exported in obj and imported it in Zbrush to sculpt some details on it. However, when I try to subdivide my mesh, 2 vertices moves. I do not know what happened, the two vertices seem to go in the middle of my mesh. Here a screen to show me problem. The left side it’s before the subdivision, the right after.
Does someone already see this and can help me or refer me to a thread that explain and solve the problems ?
Thanks.
I’m still learning so I might not know the best answer, but here are two ideas that I might check. Did you use weld on import? It could also be a scaling issue, I don’t know.
I’m sure there will be better answers.
Yeah I’m having a similar problem.
This has just starting happening recently, what could be the problem? Also, I have ZB2 and there no such problem.
No, I didn’t use weld on import, I didn’t even know this option before your answers :D.
No one have an idea of what may cause the problem ?
Check the Tool>Preview window. How large is the model in that window? If it’s extremely large or extremely small, then this could be causing the problem. In that case, you’d want to use the Tool>Deformation>Size modifier to scale the model to be nicely framed within the preview window.
If scale is critical to your import/export, though, you’ll need to keep track of how much you’ve resized it. That way you can undo the sizing before you export the model again. For example, for every time you use Size -50 (halving the size of the model) you’d need to use Size 100 to double it again. If your model was small to begin with, then you’d start with Size 100 to enlarge it. Before exporting again you’d use Size -50 to halve it.
If scale is NOT important, then just use Tool>Deformation>Unify. This autoscales the model to be a perfect fit. But you can’t return it to the original scale because you don’t know how much resizing was done.
Thanks for your help bu even if it’s good to know (it may solve furur problem), it’s not the case right know. My mesh fit perfectly in the preview windows, not too small, not too big and the unify function don’t do anything.
So, an other idea 
?
Hi,
i had a similar problem recently.In my case it was a pole
surrounded by triangles and the only thing that helped was
changing the topology to a pole surrounded by quads in the
application i modeled the base mesh in.
I’m having same problem with a lot of my imported .obj’s as well. I’ve imported .obj’s I’ve made in 3DS Max, exported from poser, and from a Gnoman tutorial dvd. They all have vertices that move when I subdivide. I can’t seem to figure it out.
Hey CRoland, I tried what aurick said. Well actually my mesh fit in the preview window fine, I tried enlarging it a bit because that 's what I thought needed to be done, but it didn’t help. Then I shrunk it more than aurick recommended and now it works fine. Try reducing the size, experiment with it, but keep track of it like aurick said. Hope it helps. 
Thanks a lot jmeyer ! It was my problem. Only converted those to quad and it works ! But it created a newp roblem , my normals are flipped. How do you recalculate the normal inside/outside in Zbrush. Is there a way to flip the normals ?
No problem. 
As for the normals:in ZB it’s Tool->Display Properties->Flip.
In case you don’t know there’s a documentation and lots of
info right here http://www.zbrush.info
Had the same problem with a very small object.
To fix that, i had to smooth once this model once, before importing in Zb