ZBrushCentral

NO color when import an obj file?

ZBrush Usage Questions
#1

Hi guys, I got a problem and can’t find a solution after searching the forum.

I got a .obj (with a .mtl file) created by my friend, he told me he didn’t use
any texture map but just assign colors to different faces of this file, so there
is no bitmap file included.

when I import this obj file into 3Ds MAX or Rhino, it looks great, all the colors
are correctly on the faces where they should be. But when I import the same
obj into ZBrush, all colors gone! only the default dark-red material of zbrush
showed…

I can’t find the solution. Could anyone help me? it’s very important to me to
find the solution, because I really need ZB to sculpt on the colored model,
and then directly export to a colored vrml file to 3D printing with the new
3D print exporter plug-in. (so if I can’t solve this issue, it can’t be done)

thank you for replying.

Acon

#2

When you say ‘color’ do you mean you’ve assigned a material to the polygons and that doesn’t import? Or do you mean you’ve assigned vertex painting to the polygons and that doesn’t import?

Anyway, I could be wrong here, but I don’t think either would import into ZBrush.

#3

to chris-carter:
thanks for your replying.

so, it’s a bug (?) of obj importing of ZB…if this can not be solved, could anybody tell me how to
covert (bake?) the color in the 3ds max/rhino to a blank texture map and save the bitmap
with the obj/mtl, so then in the ZB I can re-assign the texture map to the model?

what I mean is like the 「Col > Txr」 fuction in the Tools -> Texture palette of ZBrush
(of course a new blank texture map must be created), but how to do it in the 3ds MAX or Rhino?

thanks for any help.

#4

Hi,
when you have a model with different colors assigned to its
faces these colors should show up in ZB as polygroups.
Hope that gives you an idea.

#5

If all you want to do in ZBrush is sculpt then this may be a solution. If you want to create or edit the color then you will need to import a texture map to get the colors back.

If the coloring is through material groups:

ZBrush will import material groups but will convert them to polygroups. No use is made of the material colors so they won’t be displayed.

To import material groups you need to

  1. Switch OFF Preferences>Importexport>Import Polygroups so only material groups are imported.

  2. Switch ON Preferences>Importexport>Import Mat AS Groups

Exporting the OBJ will preserve the groups and their names (so the names of the colors) but they will have the ‘g’ tag, not the ‘usemtl’ tag. If you have a t ext editor that has a ‘Find and Replace’ feature you could easily swap the two tags after export.

#6

Thank you marcus_civis and jmeyer,

so, is there any way to convert the colors of the model to ONE texture map in 3ds MAX or Rhino?

#7

I recently exported some characters I made in zb as obj’s into Rhino 3d, I went to render them and Rhino could not render them and told me that I was missing some bmp. texture files that were to be located on the desktop. Any body know what’s going on exactly or if I’m missing a few buttons to click to get the bmp files on exporting obj objects out of zb?

Thanks!
ST:cool:

#8

Did you a create texture in ZBrush? If there was a texture applied to the model in ZBrush then it will be exported as a bmp when you export the obj. If there was no texture applied but your model has UVs then there will still be a reference to the bmp in the .mtl file.

#9

I did not have any textures applied… I will do so and try it out. Thanks for your support I really, really appreciate it…

ST