Hello. I’m relatively new to Zbrush, so please be patient 
I import my model with 2k UV map from *.obj file and apply texture by clicking polypaint -> texture form polypaint.
But texture is too huge (or model too small) so that i can see only small part of texture on subtool. It seems ZBrush ignore UV map or i’m doing something wrong. Can you please help me to resolve this issue?
Does the texture look good on the model inside of zbrush, before you apply it as polypaint? If not, you may need to flip it vertically in the texture palette first.
If it only looks bad after trying to apply it as polypaint: make sure that you have enough vertex density in the mesh to support the level of detail that the texture would contain (so for a 2k texture, you’ll want to subdivide it up to a few million vertices at the very least).
Thank you for answering. I subdivided subtool several times after import in ZBrush, so it looks smooth. I fliped texture, and do everything according to this tutorial
http://www.digitaltutors.com/forum/showthread.php?39170-Importing-existing-textures-to-model-in-zBrush
Unfortunately, i do not know how to look at texture applied to model in ZBrush before i apply texture as polypaint.
Here is some images. May be they will help
Here is how it looks in Blender3D
And here is how it looks in ZBrush
Unfortunately, i do not know how to look at texture applied to model in ZBrush before i apply texture as polypaint.
At the moment it looks like you have the texture applied as a brush texture (on the left of the screen). Use The Tool: Texture Map menu to assign it instead. You can then use the ‘Tool: Texture Map: Texture On’ button to toggle it on and off (note: when a texture map is on it will visually override any polypaint information, and you should see the texture at its full resolution regardless of how many vertices are on the current subdivision level).
As for the base model itself, it’s hard to tell from the screenshot if you have enough vertices for the texture you’re looking to project onto it. The initial mesh is extremely low and its faces are stretched very wide, which spaces the vertices further apart. This means that in order to get a nice enough blend to be able to see the grid lines and numbers, you’re going to have to really crank the subdivision levels really high. 1 million vertices might be a good starting point at the very least, possibly more in order to really tighten up the distance between the verts.
If your base mesh is not constrained to any particular polygon budget, you may be better off adding in some extra edgeloops so that the faces are a bit more square-shaped. This will help it hold its shape when subdividing, and will give you better behavior when sculpting and painting inside zbrush.
Thank you, Cryrid You helped me a lot!
I import texture as brush to flip it then apply via “Tool: Texture map” menu and it works fine. (I also subdivided model four times, so that it has enough polygones).
But when i Use “Polypaint->Polypaint from Texture” texture apply incorrect, with some distortion, like in previous time.
UPD: Now texture looks fine after “Polypaint: Polypaint from Texture” but it seems that even more levels of subdivision were necesary. I subdivided model four times in Blender3D before export to *.obj and then subdivided four times again in ZBrush. It is eight (!) levels of subdivision for 2k texture. OMG.
P.S. I plan to use model for 3D printing with color. May be i can leave everything as is, with textures but without polypaint and export model in *.wrl format in hope that 3D printing software is capable to understand UV correctly?
UPD: Now texture looks fine after “Polypaint: Polypaint from Texture” but it seems that even more levels of subdivision were necesary. I subdivided model four times in Blender3D before export to *.obj and then subdivided four times again in ZBrush. It is eight (!) levels of subdivision for 2k texture. OMG.
My rule of thumb is to try and have at least as many vertices as you do texture pixels. So for a 2K texture, you’ll want at least around 4 million verts (2048x2048=4,194,304) to hold the same amount of detail.
(You can get away with a little less if not all of the UV space is being used, but you’ll probably want to use even more vertices if they’re spaced further apart. Really if your machine can handle it then I don’t think it hurts to err on the side of having more vertices in order to preserve everything. Decimation Master will be able to crunch it all down in the end anyway)
P.S. I plan to use model for 3D printing with color. May be i can leave everything as is, with textures but without polypaint and export model in *.wrl format in hope that 3D printing software is capable to understand UV correctly?
This will depend on the type of file format and printer you’re using. Some printers (like zcorp’s powder-based ones) will be able to use texture maps just fine, others (like your basic plastic extruders) will ignore any color information and just print with whatever color filament is loaded. You’ll have to look into the specific printer you’re using to see what it will and wont accept.
If you’re hoping for the end result to be smooth and curvy, it still wouldn’t hurt to have the extra geometry present.
Thank you for detailed answer. I thought decimation master ruin polypaint info. I was wrong then.
I have no problem with amount of polygons, but i thought that Pixologic recomendation for 3D printing is that subtool must be less than million polygones. If amount of polygones is not a problem and 3D print Exporter able to handle as much polygones as i can feed to it, then i will subdivide subtool as many times as needed for proper polypaint from texture. This approach will solve all my problems.
I basically want my model some kind of universal so that most printers, even basic ones, can print it. Some with color, if needed, some without color. I even simplified geometry and adapt it for 20x20x20cm printing chamber, so that most printers can handle printing. I just want to be sure that people, if they want to, will have no problem printing my model with color if they have printer able to do this.
UPD: About decimate master. I guess i’m doing something wrong, but when i decimate model, polypaint info just disappear. I go to “ZPlugin: Decimation Master: Decimate Current” with default settings. Polygon count decrease significantly, but polypaint disappear.
P.S. I wonder, if i use vector texture format instead of raster texture, would ZBrush be able to convert it to polypaint with lower levels of subdivision required.
UPD: About decimate master. I guess i’m doing something wrong, but when i decimate model, polypaint info just disappear. I go to “ZPlugin: Decimation Master: Decimate Current” with default settings. Polygon count decrease significantly, but polypaint disappear.
You need to enable the ‘Use and Keep Polypaint’ option in the decimation master settings
Thank you Richard Marklew for your help, here and at blenderartists. I can not belive i was so blind.
UPD: But, whait. I have ZBrush 4R6 and there is no such button in decimation master
I must upadate plug-in or whole program?
Can you, please, clear this out for me: is Pixologic still recommends less than million polygones in subtool for 3D printing?
The polypaint option is stored in Preferences: Decimation Master, not the actual Decimation Master Plugin
Thank you CryridNow decimation process does not ruin polypaint info. It is great. I just can not understand why sometimes amount of polygones after decimation is even more than before, sometimes unchanged and i have to do decimation process twice to get some results. But i must be doing something wrong.
Can you please tell me, if polygone budget is still important for 3D Printing? If subtool has more than million polygones is that a problem or not?
The polycount count might depend on the printer and service you are using. Some places (especially online services) might have a filesize limit for uploads, which could affect the amount of polygons you’re allowed to use. A large amount of polygons could also affect the time it takes for any slicing software to process the mesh as well. If its a printer you have direct access to then it shouldn’t hurt to try, and if its part of a professional printing service then it would be best to ask them what their specifications are.
