Forums Technical Discussion Ptex error with imported geometry

Ptex error with imported geometry

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NFX
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Hi there. So I am trying to figure out the PTEX workflow and for the most part have been pretty happy with the results. However I've run into problems as soon as I started using imported geometry from maya. I've tried deleting the UVs, fixing the normals, exporting the model from houdini into mudbox and then reimporting it from mudbox after I'm done painting…nothing seems to be working. I've included a .zip with my file, the imported geometry, and the exported ptex file. Any chance anyone could clue me in to what I am doing wrong?

Attachments:
PtexTest.zip (2.1 MB)

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mark
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90ender
Hi there. So I am trying to figure out the PTEX workflow and for the most part have been pretty happy with the results. However I've run into problems as soon as I started using imported geometry from maya. I've tried deleting the UVs, fixing the normals, exporting the model from houdini into mudbox and then reimporting it from mudbox after I'm done painting…nothing seems to be working. I've included a .zip with my file, the imported geometry, and the exported ptex file. Any chance anyone could clue me in to what I am doing wrong?

It looks like the acorn is modelled as triangles. Clicking the middle mouse on the xform1 tile shows that there are 1,312 polygons.

When I run iinfo “ptexpainttest_Default Material (ptex)_Diffuse_Paint Layer 1.ptx” in a terminal, I see that the texture map is built for quad mesh geometry containing 3696 quads.

.ptex files are matched with their geometry, and I don't think the .ptex file matches the acorn squash.
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NFX
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How could the texture not match up if I converted it to ptex and created the texture in mudbox? It still won't work if I export the converted squash I used in mudbox back into houdini.
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NFX
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So I tested using the same model but with no tris since I read that the some people had trouble using ptex with triangles. However the textures don't work. I'm using a windows machine currently so I'm not sure how to call up the info for the ptex file to compare polycount but as far as I can tell I have not altered the mesh at all from the point that I painted on it in mudbox.
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NFX
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Finally! So I got it working by pure accident. Turns out I needed to throw down a reverse sop on the version of the model with no tris. Worked like a charm. So lessons learned is ptex does not support tris in houdini and to always try a reverse sop if things just aren't working with imported geometry. Thanks for your help guys!
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NFX
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For those that may have similar issues with figuring out PTEX in the future I have attached a zip file containing a simple example of how to set up a PTEX network that includes alpha and imported geometry.

Buen Provecho!

Attachments:
Ptex Tutorial.zip (1.0 MB)

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firefly9000
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A good tutorial but in H13 there is NO Ptexture node.

What happened to it?

Thanks
Winter is coming!
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pezetko
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Just use regular Texture VOP node.

There is no need for separated ptexture node now, so it's hidden, reading PTEX functionality is now in Texture VOP.
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NFX
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pezetko is correct. Here is an updated version of my ptex in Houdini tutorial. It now uses the texture node. Also remember that ptex does not work well with non-quad geometry, so if you have issues make sure to check your mesh.

Attachments:
Ptex Tutorial H13.zip (1.1 MB)

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