photoscan textures in zbrush

[Kms1]

Hi, ive been using zbrush and photoscan for a few months now and have been getting great results, having scanned i bring the models into zbrush for smoothing, closing, dynamesh etc

My issue is that as soon as I start changing a model in zbrush and closing holes, zremeshing etc I lose my texture, what can I do to retain the texture from photoscan and what is the best workflow with regards to maintaining texture and uv details once a mesh has been repaired or retouched in zbrush. Also any tips on retopology, some people on here are getting excellent low poly smooth meshs out of the detailed high polys that imports from photoscan

any help on workflow/textures/retoplogy in zbrush would be greatly appreciated as I see some fantastic results from people on here

thanks

[mwillis]

Export your cleaned model as an OBJ from zbrush then import that OBJ into your original PSZ file in photoscan. Build Textures in Photoscan using "Mapping Mode: Keep UV".  Export as a new OBJ from Photoscan.  That'll give you a cleaned OBJ with textures.

Cheers,

Mark

[Wishgranter]

a small trickery..... on the new repaired mesh, create new UVs, export OBJ import to Zbrush, generate texture as mwillis say. SAVE texture . go back to zbrush an just load texture on the  mesh.....

[Kms1]

amazing! i had no idea you could re-import into ps the edited mesh from zbrush!

worked a charm, i just have to correct a few minor things in the texture which i guess i could do by editing it flat in photoshop, hope to obtain a simpler texture map by uv unwrapping in zbrush or 3ds max (?)

thanks so much guys

i thought u had to use uvmaster on the mesh in zbrush, then repaint on the texture somehow in polypaint, this saved me hours

[cuongfvuong]

Dear,
I do as you said, but when I built the texture again by the OBJ exported from Zbrush, the new texture is just a mess.
Anybody help me, what did I do wrong?

[Kms1]

did you rotate, move or scale the obj in zbrush? if you did the uvs will be altered and will not line up when reimported into photoscan

[hzdbsm]

you can use normal baking.

[DanilaNovikov]

Hi there guys! I srtuggle to prepare raw scaned mesh usung Zbrush I've overcome a bunch of issues durring this way in wich this topic helped me so much. Now I stuck on step when I try put prepared unwrupped mesh back into 'Photoscan' aiming to project texture on it. But this prepared mesh has several tims smaller scale than original mesh that I want to take texture  from. What I have to do to avoid this differense in scale betwen them?
Thank you in advance.

[igor73]

Check the export settings in Zbrush.  You are probably scaling it down when you export.   The export setting should be left untouched.   Only thing i change is disable  groups  to avoid polygroup splitting of the obj.  Do not change the scale setting of the export setting.  Normaly it shows something else than scale 1.0.  Leave it as is and you should be fine. 
If that does not help you must have changed the scale of the sub tool with out knowing somehow.  Not sure how you would reset it. 

[DanilaNovikov]

Tnx u Igor 4 answer. You are great! The export scale values should be set to 5.38 instead of 1.0. Now I am still unhappy since I get meaningfull different position by xyz between meshes. While I am trying to work it out, could you give any idea to fix it?

[DanilaNovikov]

Having 41 poligroups about, 1.5 million polygons at them I run out of memory durring unwraping map in Zbrush. Do you guys have any idea how it possible to deal with this.

[chrisd]

Having 41 poligroups about, 1.5 million polygons at them I run out of memory durring unwraping map in Zbrush. Do you guys have any idea how it possible to deal with this.

ZB4 R7 was recently released with a 64-bit version. That may help.

[igor73]

I have not got UV master to work with more than 150K points.  Polygroup in a logical way helps but still can´t get it to work with more that about 150k points.  Keep in mind that the UV process can take a lot of time if the mesh is complicated. Can take up to 40 min and you will think Zbrush crashed . 

You have to re topo the mesh or decimate it using UV master to get the point count down below 150k. 
Re topo can be done quite easily using Z remesher and then you subdived the mesh after and re project the details.
Search for z remesh tutorials.  Pixlogic has some on their site and plenty on youtube to.   

If you get UV master to work with more than 150k points let me know.  I have 4r7 and there seams to be no diffrense in UV master.   There is a big difference in being able to handle mesh with up to 80 milion points now though wich is great.  Before it was "limited" to 20-25 milion points. 

This tutorial explains it all on an interesting exaple model to  :-) https://vimeo.com/83681474
He used an older version of Zbrush though.  Polygon bridging can now be done i Zbrush using Zmodeler. 

Last resort if you can´t re topo or you don´t want to bother is to either use Zbrush other auto UV tools like UV tiles.  You find them under tools and UV Map.  They handle more  points but you get a Agisoft style UV that you cant edit later.

You can also bring the mesh back in to Agisoft and let Agisoft make the UV.  Test Adaptive Ortophoto mode , it actually keeps your UV quite intact although with some streching depending on what kind of mesh you have.  If its mosltlöy a flat model Adaptive Ortophoto will be good enough and make a mesh that you can edit in photoshop. 

[chrisd]

If you get UV master to work with more than 150k points let me know.  I have 4r7 and there seams to be no diffrense in UV master.   There is a big difference in being able to handle mesh with up to 80 milion points now though wich is great.

I think Pixologic indicated that the 64-bit version was a beta, so perhaps they are not done coding all the functions to make full use of the increased memory.

[igor73]

Im not sure, UV master might handle more points now.  Have not done enough tests yet.  I unwrapped a 194k dynameshed mesh yesterday and it actually worked well.