ZBrushCentral

Need help on UVW and displacement!

ZBrush Usage Questions
#1

Hi,

As some of you know i’m new to 3d but i’m trying my best to become good at this.
I’ve recently learned about displacement mapping bump mapping and normal mapping.

First of all these 2 questions:

1.I am working on a mesh consisting of nearly 2mill polygons…displacement mapping is supposed to cover a low poly mesh in the same position as the high poly and keep the details of that high poly mesh as long as the uvw is the same…right?

2.mapping is used mainly to keep projects smaller than it would be when using no mapping, so that your computer can handle more…right?

Now here is the real problem:

I want to make a displacement map of my zbrush model, but my UVW’s arent right! thus disabling mapping.

I don’t understand how to fix the uvw’s on the model!

I tried to fix this by importing the high poly model into 3ds max but my computer cant handle that! and I don’t think exporting would do any good anyhow, because my model wouldnt consist out of subdiv lvls anymore…

Please help me! I fear all the work I have done on the model was good for nothing if I cant get the UVW’s right!!!

Slice

#2

have u tried to read Displacement FAQ???

im saying it cuz the ZForum is full of Displace problems…

  1. you can use Zbrush’s UV mapping - AUV or GUV Tiles

  2. Use another software to manually create UV’s.

Luck!

#3

He thank you for replying,

and yes I have tried the FAQs but none of them helped me…

I’ve tried fixxing the UVW using the AUV and GUV tiles following one of the tutorials on the ZClassroom, but those didn’t help me either!

The problem is, I really wanna fix this, and normally when I run into a problem I’m working at it for days until it works exactly like I want it to…but I don’t understand UVW so creating it manual would be hard…especially with a 2 mill model…right?

I got Deep UV -right hemisphere for this by the way but that couldnt load my model either…
Would you know the answers to my first 2 questions??

Thank you!

Please comment if you have any idea how to solve this!!

Slice

#4

Was your base mesh created in ZBrush or another app?

If it was created in ZBrush:


  1. Go to level 1 of your model
  2. Export
  3. In your other app, lay out the UV’s that you want. Be careful not to change the point order of the model. (That includes your import/export settings.) Export the UV’d model.
  4. Back in ZBrush, make sure your original model is still selected and still at level 1. Import the version with the new UV’s.
  5. Turn on Tool>Geometry>Cage. If you don’t care for the look of the cage at that level, try going up to level 2.
  6. Create your displacement map. Flip it vertically and export it. Also export your model again, while Cage is still turned on.

  7. In your other app, import the cage OBJ and apply the displacement map to it.
If it was created in another app:

  1. Open your original model in your other app and lay out the UV’s. Export it. Be careful to not change any settings that would affect the point order.
  2. Back in ZBrush, switch to the morph target that you stored prior to dividing the model in the first place. Didn’t store one? No problem; do so now.
  3. Import the new version of the model with the UV’s.
  4. Create the displacement map. Flip it vertically and export it.
  5. In your other app, apply the map to the model that you just did the UV work on. No need to export the model from ZBrush in this case.
In this second situation, the morph target is there in case you decide you need to return to higher levels. After step 2, any time you need to go to higher levels switch to the stored morph. When returning to level 1, switch morphs again to get your cage mesh back.

#5

He Aurick thanks for replying, I’ll try following your instructions although I need to learn more about uvw mapping before I can be succesful…

Anyway thanks for helping me, now I know what to do

#6

Slice,

Part of your confusion may be that the "import" button really has two meanings (which I know has confused my students in the past.) Most of the time, it does the everyday thing, which is to take in a .obj (.dxf) file and make a polymesh3D out of it.

However, if you already have a sculpture loaded as a tool in “edit” mode, the import button has a magical property at Level 1 (the lowest resolution of your sculpture): Import will replace the Level 1 mesh with the imported mesh, including it’s UV information, provided the imported model has

  1. the same number of points
  2. the points are in the same order

So how do we use this to our advantage?

Well, ZBrush has somewhat limited UV’ing tools. The only ones that avoid significant distortions for most common sculptures are UV tile options like AUVs, GUVs, and PUVs (note that the “tile” button maps every polygon to the same UV space–OK for repeating textures, but not really what you want for most sculptures.) These tiles are sometimes OK depending on your application, but since they are pure computer generated, they tend to look like confetti if you opened a map in a image making application like Photoshop. Since these are visually hard to work with in image applications, many artists perfer to unwrap or create a “pelt” of the surface of the model. Today, Zbrush doesnt really make pelts.

The solution to getting a pelted UV map is to use an external tool. I use mostly Silo, Modo, or UVLayout for this job. The procedure is as Aurick has outlined. I export just level 1 of my model as a .obj and load it into my tool. I then use the tool to cut slices in the object (imagine cutting its surface with scissors) and then flattening it.) When I have a UV pelt I like, I then save my .obj with the new UV map. I have changed any points or re-arranged their order, so I’m good. Then I go back to ZB, load up my sculpture, set it to level 1, and import this updated .obj file. Like magic, ZB imports the UVs and now I can use ZB’s mapping features (Muti Displacement 3 or Zmapper) to create my maps.

To get a feel for what’s going on in creating UVs, I suggest you watch the videos of Headus UVlayout in action–this should give you the flavor of the workflow. They can be found here: http://www.uvlayout.com/index.php?option=com_wrapper&Itemid=67

The home pages:
UVlayout: http://www.uvlayout.com/
Silo: http://www.nevercenter.com/
Modo: http://www.luxology.com/

-K