UV’s

UVs are two-dimensional texture coordinates that reside with the vertex component information for polygonal and subdivision surface meshes. UVs exist to define a two-dimensional texture coordinate system, called UV texture space. UV texture space uses the letters U and V to indicate the axes in 2D. UV texture space facilitates the placement of image texture maps on a 3D surface.

UV Mapping

The process of creating explicit UVs for a surface mesh is called UV mapping. UV mapping is a process whereby you create, edit, and otherwise arrange the UVs (that appear as a flattened, two-dimensional representation of the surface mesh, over top of the two-dimensional image to be used as a texture as it appears in the UV Texture Editor.

Practical UV Explanation

UV’s are the visual representation of the three-dimensional polygonal model in a two-dimensional space. Think of taking a shirt that contains volume, removing the stitching, and flattening the various clothe pieces flat. That is the of equivalent of what must be done to a 3D model.

Auto UV

There are a number of ways to project UV’s. The basics are planar, cylindrical, and sphere. Zbrush has a method that will automatically produce UV’s. The results vary but they may be completed very quickly.

UV Master

This plug in will “pelt” your model. The results are pretty decent for being automatically completed.

Materials

In the real world, what an object is made of is one of two main factors that determine the appearance of its surface (the other is light). This is because when light hits the objects, some of the light is absorbed and some of it is reflected.
Factors beyond basic color, transparency, and shine that determine the appearance of an object’s surface (such as more complex color, transparency, shine, surface relief, reflection, or atmosphere) are defined by textures.

Texturing:

We input various raster images or poly-painting to attributes of the shader in order to assign values to specific areas of the mesh. These attributes include things like color, bump, and specular (checker below).

Poly-Painting:

ZBrush utilizes poly-painting. Unlike other methods where you paint a two-dimensional raster image that lays over-top of the model in this process you color the vertices of the model. This means that the resolution of the texture is based on the polycount. This is not generally useful for final production. The advantage however, is that you may texture a model independent of the UV’s and back them to an image afterward.

lower resolution polys result in lower resolution texture

You can see at lower resolutions how the vertices are the sources of coloring. 

The higher the resolution the higher the fidelity.

Texturing Process:

Like all projects it is best to work broad to specific.

Texture Painting Process:

Primary Colors

The first step is to simply apply the main areas of color over the entire model.

Secondary Colors

After the entire model has been painted the next step is to paint secondary colors, things like patterns, stripes, logos, text, etc.

Variation

Apply varied colors that broadly appears like the primary and secondary coloring (ex. if you look at skin you will see a ton of variation).

Textures

Using both color and bump mapping you will add the texture of the surfaces.

Details

Add minor details. You should attempt to produce surfaces that show history. This is usually best achieved by using grunge maps.

Pre-Shading/Rosiness

In order to make a model really pop it is usually best to darken areas that recede and lighten areas that ascend. It is also a good idea to add redness at the superficial areas of skin.

Export:

Once the model is complete you need to get it out of ZBrush and into whatever package you are using in your production.

Export Settings:

Select ZPlugin > Multi Map Exporter. You should apply the settings in the image at the right.

Production Implementation:

In order to use what you have created in production you must export the following:

• Lo-Res Model: The lowest polycount geometry acceptable should be utilized for more responsive playback in games or video production.
• Diffuse/Color Map: This obviously holds the hue and value information. This is the most important texture image.
• Specular Map: If the model has varying “shininess,” then an achromatic (usually) texture image is used.
• Normal/Bump Map: This texture stores the detail and surface irregularities sculpt on the high poly model as an image. This will “fake” the details onto the lower res model.
• Specialty Maps (transparency, incandescence, height, etc.): Other texture images may be used to apply different properties to the model’s surface such as being see-through or light emission.

Did you remember to?

• Read through this webpage
• Submit Human Texture Lab on Blackboard