Ptex - Mudbox - HighRes Mesh ?

[bernhard]

Mudbox: -->export the HighRes Mesh as .obj or .fbx.

I load the .ptx difuse file into the vray shader, assign it to the geometry and this is what's happening:



you can see on the left side, the low poly sphere.. and on the right side the high res.
The .ptx difuse layer fits on the low res, but doesn't on the high res sphere.

So what am I doing wrong here ?

[Morbid Angel]

my guess is that ptex is point order dependent, point order is different no ptex

[bernhard]

hmm.. well. what ever.. but the .ptx file should fit perfect on the geometry when rendering the difuse... even on the highRes geo... I mean, it fits to the lowRes, why does it not work on the highRes ?

[vlado]

hmm.. well. what ever.. but the .ptx file should fit perfect on the geometry when rendering the difuse... even on the highRes geo... I mean, it fits to the lowRes, why does it not work on the highRes ?

Because it can't work. The Ptex file contains information for the colors face by face; if the face count in the Ptex file is different from the face count of your model, the renderer can't make the connection between the triangles of the high res mesh and the triangles in the Ptex file. Instead, you should use the VRayDisplacementMod modifier in "subdivision" mode to subdivide the low-poly model.

Best regards,
Vlado

[bernhard]

hmm.. makes sense vlado .... well.. I rather want to use the high res geometry in combination with a vray proxy...but that means, I need to create the .ptx file based on the highRes poly mesh... holly molly.... that's a challenge and a RAM eating machine...lol;
like always... thx for the info, appreciate it !!!

[Morbid Angel]

this was a major work flow issue for me. Your geometry ends up changing often during production that's just how things are. You cannot expect to transfer your ptex paint everytime. Not very efficient in my opinion, if various meshes share same uv's they can use the same texture, but not with ptex, one map per geometry tessellation if you will.

[bernhard]

yes.. that's a very good point... I really thought it would work with the highRes Subdivs as well... hmm... ok.. one more thing.. when exporting displacement map and vector displacement.. what are the recommended export options from mudbox ? when using .ptx files ? and what are the settings for the VraydispMod in the max stack ?

[PIXELBOX_SRO]

Hi guys,
sorry for a slightly OT question, but i would very much like if someone cleared this to me:
if i use PTEX, and lets say i have a model with different size of polys and i want to draw a very hi res texture on top of very small poly....
will this actually end up vene more subdividing my poly or not?
in other words...will drawing a 32K texture on a normal res mesh end up subdividing my entire geometry?
Thnaks a lot!

[FSGFX]

ptex is not subdividing your mesh... its creating a texture for each face... but the trick is ptex does know which faces are sharing an edge...
and you are able to upres the per face texture on selected faces...

http://www.youtube.com/watch?feature...2CYEvfI#t=412s

[PIXELBOX_SRO]

thanks for the explanation and the link!!!