Hi guys.

I've been trying to use pTex on my current project however I must say that it turned out to be fairly unsuccessful.

My workflow is very straightforward:

Create mesh in Houdini or Maya
Export OBJ into mudbox, setup ptex and paint
Export maps as .ptx files from Mudbox
Export model export model as OBJ from mudbox.
Bring model into HOU, apply Mantra Surface
Inside Shader create pTexture, hook base color map into it and connect output of pTexture into diffuse on the surface model.

Pretty much the same steps as here http://3dsurvival.hu/index.php?option=com_content&view=article&id=197%3Aptex-workflow-mudbox-houdini&catid=54%3Acikkek&Itemid=37 [3dsurvival.hu] . However I'm using model from houdini not mudbox.

The problem is that the faces seem to be scrambled. I've encountered 3 types of scenarios so far.

• The sample files from ptex web (http://ptex.us/samples.html [ptex.us]) work without problem out of the box
  Geometry created in mudbox and brought into houdini needs to have either reverse sop applied, or u a v coords switched inside of the shader
  Geometry created in houdini a passed through mudbox and back is completely hopeless.
  
  It looks to me as if the faces get reordered somewhere along the process of exporting mesh to and from mudbox, as the assigned texture is not only rotated on each face (which can be fixed by reversing) but they are simply assigned to completely wrong faces.
  
  Has anybody successfully used ptex on something else other that sphere and torus?
  
  Any comments appreciated.

Take a look on Match Topology SOP [sidefx.com]. It may help you reorder points/faces in imported geometry to match original one (if that's the case). I would be seriously surprised, if that's Houdini false. In years of production I haven't seen a single case Houdini has changed ordering without a reason, unlike xsi/maya/max which constantly export garbage that has to be repaired with MatchTopologySOP.

As a side note, Ptex workflow is seriously incomplete without remapping solution, since it locks your geometry mesh to texture image, which basically stiffens a pipeline unnececerly.