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obj export questions

ZBrush Usage Questions
#1

Hi guys,

I have a few questions related to problems I’m having with exporting/importing OBJs from Z-brush to MAX.

  1. I exported my model from z-brush at the lowest subdivision level to bring into MAX and set up UVs. When I bring the model back into z-brush, the different subdivisions are fine, with no expoloding polys. All is good except that the model is not the same size or placement. I didn’t change anything in Max and have even experimented with exporting the model as an obj and then immediately importing back into z-brush, getting the same result, even with no editing in max or any other program. The model is a head and when I bring it back into z-brush, it’s much lower and the eyes are just floating in space and out of proportion. Any thoughts on this?

  2. My second question is that I made a model with z-spheres and added more resolution at the first subdivision in a certain area. When I go to export it and re-import the obj, only the area that I added more resolution to explodes. I can fix this by deleting the lowest subdivision, but could someone explain what’s happening with this.

Thank you for any help you might able to offer. Both models were generated with z-spheres.

#2

For question 1, have you set a pivot point? If so, try clearing it before you export.

Your second question is simple: When you modified the mesh in your other app you change the point count and order. This destroyed the hierarchy that links level 1’s points to the higher level points.

#3

Hi Aurick,

Thanks for the response. Focusing on the second question, I didn’t modify it in the new application (MAX) outside of adding UVs to to it. When I made the model in zbrush initially, I followed the following workflow.

  1. Created the tool with z-spheres and made polymesh.

  2. I then added more detail by subdividing it into four different subdivisions, getting a warning if I went any further with a fifth subdivision.

  3. I went to subdivision 1 and divided ONLY the head area, adding more resolution to it.

  4. I modeled out the details in z-brush and exported the OBJ to max at subdivision 1 to set up some UVs.

  5. In Max, I set up the UV’s and re-exported the OBJ, not touching the geometry in any way.

When I bring it back to z-brush by importing it into the z-tool, only the area where I had added more resolution in the head explodes. The rest is fine.

This workflow has worked well with every other model I have worked on.

Thank you so much for the response and let me know if this might give you any more ideas about what might be causing this or a good workaround. When I delete the bottom subdivision and export the model, with subdivision 2, becoming subdivision 1, the problem is solved, but the model is a bit on the heavy side for setting up UVs.