Character Creation Module 08

Projecting Details and Creating Maps

Introduction
Module 09, the home stretch!!

It’s time to combine the beauty of your design sculpt with the expertise of your hand crafted organized mesh. This module will cover several options for transferring sculpted details from your design sculpt to your organized mesh. This is not an exact science but with the tips and techniques presented below you should be able to make relatively fast work of the process.

Project Between Subtools
This is a great way to transfer details from one mesh to another. Let’s go to the video to learn about the intricacies of this process- then we’ll talk about ignoring it!

https://vimeo.com/41354923

Video: Projecting Details Between Subtools

  • Overview
  • Create a “smooth” version
  • Overcoming exploding points

 

Two Beasts in Separate Cages
It used to be common place to transfer all of your details onto an organized mesh and try to push that “all-in-one” mesh down the production pipeline. That approach can still work, but I have found that keeping the two meshes separate can be even more beneficial, and easier to manage. The high res mesh will not be put into the pipeline. It’s the organized mesh that moves forward with the maps (texture, displacement, normals, bump, etc.).

Before we talk about generating maps we need to discuss the idea of UVs.

UVs
If you are completely unfamiliar with the concept of UVs, the amount of time and effort it would take to master them could easily fill an eight week course. I’ve included a brief overview of UVs in the following notes but if you have no prior experience you might consider also taking a UV centric class. In addition to a brief overview, the intentions of the following notes are to share several concepts of how UVs can be utilized to help your character creation process in ZBrush.

On the most fundamental level, UVs allow a surface to hold color and texture information, including displacement, normals, and bump.  All textures are 2D.  UVs dictate how a 2D texture will be mapped onto a 3D object. A simplified example that illustrates this point is a globe. If you want to lay the surface of a globe out flat to create a 2D texture you would need to cut it in a predefined pattern then flatten or “pelt” it like the image below.

 

UVs tell a 3D application where the cuts were made that allow the surface to be pelted. They also tell it how much of the 2D texture space will be allotted to each part of the 3D object.

3D objects can be cut into several pieces and pelted into the area of a 2D image. The example below by Kevin Lanning shows how complex the process can become. Fortunately, there are several software available today that largely automate this “layout” process. One such software plugin can be found here http://rd3d.com/dtools/ Kevin’s example showcases a great use of space and optimized UV layout. Notice how the segments of UVs are arranged to fill as much of the UV space as possible. Also worth pointing out is that only half the model is pelted onto the two separate image maps. One map being allocated to the head and the other to the body. This is a very common practice in Game UV setup. The separate map setup, or multiple texture tiles, allows for more detail to be applied to the face through one large texture map and both the head and body textures will be mirrored across the center to save memory. Further down in this module we will be exploring the idea of multiple tile textures.

 

*Just like Nurbs surfaces, UVs will never go away!! Right?

Ptex
Now that we have covered the basic concept of UVs, it’s important to mention that they will probably not be around much longer! In fact, we no longer use them at Disney Animation Studios and many other studios are already eliminating UVs from their pipelines. Ptex is a way to paint directly onto each polygon face. This virtually eliminates texture resolution issues as each face can have a map of up to 8K. Mudbox has already integrated Ptex (in a VERY buggy way) and we have already started discussions with Pixologic regarding integrating Ptex into ZBrush.

UV Layout
What used to be an extremely painful process has been transformed into a fairly simple and straight forward task. Here is a great link to a plugin for Maya that can help you make fast work of your UV layout. http://rd3d.com/dtools/. We will not be covering the basics of applying UVs to your mesh in this module because it has become somewhat of an automated process. Instead, let’s use our time to look at a few specific topics that can help you navigate how the majority of Studios generate and use maps today.

Maps Overview
Bump- Bump maps are gray scale images that are applied to a surface to give the illusion of surface change. They do NOT impact the silhouette of the surface or physically move it.

Displacement- Displacement maps are gray scale images that, when applied to the surface, physically move it and impact the silhouette. They are commonly used in Feature Film and Game Cinematics.

Normal- Similar to bump maps, normal maps are images that are applied to the surface to give the illusion of surface change and do NOT impact the silhouette of the surface or physically move it. They are RGB images and are commonly used on in-game meshes.

https://vimeo.com/42551365

Video: Generating Multiple Tile Texture Maps

  • Multiple Texture Tile UVs, 0-1 space
  • ZBrush Overview Settings
  • 32bit displacement
  • Bump, Normal, Displacement
  • Creating your maps

 

Multiple Tile Maps
As stated in the videos above, multiple tile maps are a common practice in a number of studios today and I would highly recommend gaining a basic understanding of their creation and application. I’ve included the graph below for you to use as reference as you create your maps and prepare to use them on your model at render time.

 

32 Bit Floating Point Maps
The ability to hold great amounts of detail with more predictable results and easier setup for rendering has made 32 bit floating point maps a staple in the Entertainment Industry (at least in film). They capture displacement information within a wide range of black to white value “whiter than white to blacker than black” and typically do not need to be adjusted to account for object size and world scale at render time.

16 Bit Maps
16 Bit maps can do a great job of recreating detail through displacement. They are much easier to manage, and much smaller in file size than 32 bit floating point maps. Because they are so much easier to work with, they are also a great way to start your journey into the world of mapped detail and test the process you are using to create your maps. I’ve added the link below to a complete displacement test, with the .ZTL file, multi tile maps, and the Maya file to showcase how everything is assembled. You can also use the Maya file to test your own maps by assigning the shader to your model and replacing the maps with yours. Just make sure you move your maps into the appropriate tile space!

Conclusion For Map Creation
Overall, I view these technical exercises as secondary to the creative choices that define your design. Many of you will be able to walk through the steps for projecting mesh details, or importing/exporting UVs after the first time you view the process. On the other hand, creating a GREAT character design is a craft that takes years to master. No matter how much effort you put into it, there is never a guarantee that every design you create will be great, or even adequate. When you compare those two points I hope it’s obvious which skill set will make you a more valuable asset and a more desirable employee. These technical points are important to understand, but don’t lose site of what skills will truly define you and your art.