Bad .obj files, please help to determine the problem

system · July 4, 2019, 5:47pm

Hi everyone

   I am still very new at ZBrush
   
   I have been working the last 6 years with Rhinoceros [http://www.rhino3d.com/](http://www.rhino3d.com/)
   The software has the capabillity to exporting to most of the popular file formats
   and many others I have never even had the need to work with
   
   .obj file extention it one of the wellknown ones I export to for other purposes
   on a regular ocation
   
   Attached is a .obj file of a fantasy creature that takes me not more than 10 minutes in rhino.
   
   1.The rhino render of the Beholder
   2.The .obj file imported as a tool and placed on the canvas with "frames" on
   3.The "divide" function used with "smt - aka smooth" ticked
   4.The divide done to 5th level with "smt" unticcked, but then in "draw" mode smoothed
   
   In both 3 and 4 the areas where there are joins the pollies disappear where ever joins seem to be as those functions are excecuted, and the object/tool becomes totally useless
   
   Please can other users please check the .obj file out and give suggestions as to how to remidy this problem
   
   The smae happens with .dxf exports from Maya

I included the image and .obj in one zip file for the jpg or gif did not want to apear after uploading, if someone can help with that too, please can you

   Cheers
   
   SagaN

Attachments

Full.zip (471 KB)

mitch-a · July 3, 2019, 2:15pm

hi

i think it´s becouse u have tribbled polys in your object
try to avoid tris

system · July 3, 2019, 2:15pm

how would I avoid this?

mitch-a · July 3, 2019, 2:15pm

i think that zbrush only handles quads ( hope i´m right), so try to model only with quads

system · July 3, 2019, 2:15pm

I had that thought too but when you click frames then the top and bottom of the sphere tool has triangles?

billrobertson42 · July 4, 2019, 5:47pm

When rhino exports .obj, it creates a lot of seams in the mesh. Here are some of the seams in the beholder mesh (in green)

That will eliminate the seams and allow you to subdivided the mesh w/o it splitting apart.

There are other problems with rhino meshes though, in that the way it tessellates objects tends to lead to objects that don’t subdivide well and are difficult to detail in zbrush.

Attachments

goilo · July 3, 2019, 5:55pm

Damn, these forums are real helpful… I’ve been struggling with imports from Rhino “blowing up” when sub-divided… but this method solved the problem (the mesh is still not as good as a native zbrush but it is a helluva lot better than before.)