back from ptex to uvs..

#1

plain and euh… simple…

I sculpted and painted a model but used ptex instead of uvs for good reasons (at the time)
I made sure that rendering in Vray was possible with ptex (for vector disp and paint)
this way, I end up animating a low rez obj mesh in 3d max , textured with ptex paint and displaced with ptex vector displacement map…

it works fine but…

I 'd like to switch to an other render engine which DOESNT support ptex (nor vector displacement)
(for vray rendering of vector displacement and ptex paint you have to use vray proprietary functions which are disabled when using an other render engine)

So… How can I transform my 8+millions faces model from ptex to uv ? is that even possible?

the solution has to be able to read a multi subdiv model (base mesh and the hierarchy of subdiv up to level 6)
and give me the ability to reorganize mapping from poly to ptex tiles into poly to UVs

I was even ready to toss the displacement and directly animate the 8 millions face model (driven by a low detail mesh, with skin wrap)
but even with this workaround yet I can’ t retrieve the paint because for this i d need to transfer paint from the ptex high rez model to a hi rez model that I d re- uved
And it 's virtually impossible to build UVs on a multi million mesh.
(neither “3d coat” nor “unfold3D” unwrap functions can really handle such a monster mesh. Not to mention it s a manual work I couldnt handle )

is there a way out or am I stuck with vray? (NB: i wanted to render in “fstorm”, which doesnt support ptex yet)

#2

You can UV master or manually UV a loRes mesh of your model.
Have a displacement so you have all your subdivision details and you can also export a texture map through Zbrush or wherever you textured your model from.

#3

Hi!
thanks for your reply !
but I m not sure to get you:

to be blunt, I ve done the 6 subdiv model in mudbox (not discussed in this forum , so I figured I d go in zbrush topic (was right :p)

i also practice zbrush if needed)

I 've already tried to export the low rez level to an obj, cleared the ptex UV in 3dmax, unwrapped some UVs on it,
in order to try to import uv on the low res level of the sculpt…
but mudbox doesnt let me import the uv of this low res obj on the lowres level of the model (it says “not possible to import uv on ptex model” :argh: )

I also tried to extract displacement from highres level 6 ptex model to the low res uv-ed model
and it just give a map with all details tiled like the ptex
(just as if I d texture the uv model with the ptex map,projecting the tiles of the ptex on the uv layout, see what i mean? (below pic) )
If I apply on the low res mesh, I get exactly what the below texture suggest :
the details are not mapped on the right polys because the extraction doesnt track the faces from the ptex layout to the uv layout

any idea?

I must miss something somewhere. the Ptex tech is supposed to let you paint and all , and then apply the paint or displacement to a model that is uv-ed later

#4

ok, got it now:

I was trying to do the trick with (displacement) texture extraction only…
Actually, even for displacement (as for diffuse paint layer) the transfer from ptex model to uv model happens in the paint transfer function
you have to create a layer for displacement in your ptex model (you don’t have to when you just create a displacement map for external use)
Once you have this layer of displacement , it s considered like any paint layer so you use the transfer paint layer function from your original low res ptex model to the low res uv-ed model

#5

Woah that map looks gnarly :cool:
Glad you got it figured out !