ZBrushCentral

GoZ wont allow me to change normals

ZBrush Usage Questions
#1

This is a simple (read: infuriating) problem. I realized that the displacement maps Ive been working on were getting messed up due to some of my normals being accidentally reversed on my model. Naturally I simply hit GoZ and figured id fix the normals in cinema, then GoZ it back. Easy right?

Except… every time I GoZ (or import for that matter) the model with the fixed Normals back in, Zbrush politely informs me “Mismatch points order detected and corrected” and the normals are still backwards!

What the hell is the point of GoZ if it just deletes my changes when I try to implement them???

Does anyone know a way to fix this other than importing the fixed model as a subtool and projecting every SubD level onto the new mesh? Because thats just a stupid amount of work to do to reverse the normals of 50 polygons.

I have also tried to flip the normals at the highest subdivision level, the mesh just goes bat****.

Any takers out there for some help?

#2

Not sure of a workaround at this point but I’m definitely feeling your pain.

#3

Can you test to do a traditional OBJ export from C4D and then, doing a traditional OBJ import over your mesh in ZBrush?

I’m pretty sure you will have the same Vertex reorder operation, but I would have a confirmation.

Can you confirm that you :

  • send your base mesh from ZBrush to C4D
  • then in C4D flip some polygons normals
  • send back your model in ZBrush
  • ZBrush let you know that the vertices has been reordered, then ZBrush fix the model and looks like it was on the first step.

Can you confirm? If not can you give us some steps / files to reproduce the issue ?

Sorry to not answering earlier, I missed this thread.

#4

I can confirm your test. It reorders the points on the test sphere from Softimage. However, on my production asset I didn’t actually have any polys flipped/inverted.

Is there a way to re-order point order and have the ztl inherit that new point order, rather than fixing the imported obj? Or must the end user go back with the new base mesh and reproject all the details?

Thanks for your previous reply and look forward to hearing back from you!

-Wayne

#5

yes, I think the best workaround would be to clean the mesh first, by reimporting back the modified mesh in ZBrush as a new subtool, the doing a traditional / manual reprojection of the original mesh to the new one, and then, continue using GoZ as usual.

To have the GoZ -or- OBJ file format and allowing the swap of the base mesh, the 3D internal structure must be the same, that’s why ZBrush force the reorder to recreate the original exact mesh (except the vertex position which may change).