● Now create a second strip as we did with the Topology tool, but make sure the side that connects to the fi rst strip turns red as you drag the polygons along ( Figure 3.25d ). This will ensure that the mesh stays connected and there are no unwanted seams.
Other Retopology Workfl ows
As mentioned earlier, retopology doesn’t have to involve a specifi c set of tools, and if you are more comfortable with the control of Append Polygon and Extrude , those are very capable tools for the job. The key is to have surface snapping enabled, and a good visual setting (such as Ghosted Shade Mode for the base model) that will allow you to work effi ciently.
Materials and UVs
Beyond modeling, a whole visual aspect goes along with working in 3D, and in this section, we will step out of gray and into color! There is a simple way to add color to polygons, which we address in the following section on Silo materials, but that alone doesn’t address the complex patterns and intricate art that often needs to go into a fi nished product—that’s where the UV tools come in. UV tools occupy the last several sections of this chapter.
Materials and UVs are often the departure points for work on a model in Silo, in the sense that they are the last level of polish you can add before heading to a third-party program for rendering, painting, animation, and so forth.
Fortunately, Silo integrates beautifully with these third-party programs where you can do the additional work that will produce something like the art you see on the cover and at the end of this book.
FIG. 3.25 The Surface tool allows users to quickly drag out rows of new polygons snapped to a base mesh.
Surface Tool; Create Surface Tool Shift P;
a shirt, hair, and skin for the primitive base bust. Feel free to select any colors you like, just make sure they are distinct enough to be noticeable.
● To start, open a new project and insert the base bust ( Create > Custom Primitive > Base Bust ).
● Now open the Materials Editor using one of the methods listed previously and create a new material using the New button.
You will notice four color options: “Diff use,” “Ambient,” “Specular,” and
“Emissive.” “Diff use” is the main setting we’ll be working with here. The rest deal with how coloring reacts to diff erent kinds of light.
● Once you have created the new material, click on the colored square next to the “Diff use” setting and change the color to one appropriate for hair. Name this new material setting, and then create two more new materials—one for the shirt and one for the skin, in whatever colors you like.
● Now enter face selection mode and select the areas for the hair. Then, in the materials editor, select the appropriate material and press Apply .
● Repeat the process for the shirt, and you should get something like Figure 3 26a .
Rather than trying to select each of the remaining faces individually for the skin, we’ll use one of the great features of the Material Editor: Select By .
● Select the default material in the editor, press Select By , and you should see all of the remaining polygons selected (as in Figure 3.26b ). Select your skin material, press Apply , and you’re done.
UV Basics
UV tools are some of the most diffi cult to understand in the Silo toolset because they involve new vocabulary, a new viewing style, and a new way of thinking about your model. In addition, unlike some of the other concepts we’ve discussed, working with UVs doesn’t involve as much iteration—it’s more like a recipe of small steps—so it’s important to catch them all. This section includes a mini project: creating a T-shirt UV map to help you understand the fl ow and process.
To start, it’s important to know what UV stands for and why UV tools are important. The letters U and V represent the two axes in a two-dimensional view of the polygons that make up a 3D model. This 2D representation or UV map contains a fl attened-out version of all of the polygons, broken along seams into groups. The map is used as a template to create detailed textures for a model, a process that happens outside of Silo in a painting program. The textures are then imported into Silo and wrapped around the model, much like fabric or skin, according to the map.
Perhaps the best way to get a sense of how this works is to see a fi nal UV and painted texture. In Figure 3.27a , it might be hard to tell at fi rst, but what you are seeing is a model of a female character that has been fl attened for UV work. The head was cut down the back and was laid out in two halves along with a mid section and other parts of the character’s body. This map was then exported from Silo for painting ( Figure 3.27b ) and reimported for use on the model ( Figure 3.27c ). For now we won’t try to produce anything this complex (more to come in Chapter 13), but we will look at how the tools can work on some basic models.
UV tools fall into a few categories: seam creation tools, UV unwrapping and placement tools, and UV manipulation tools. In this chapter, we walk through FIG. 3.26 A base bust with three materials applied.
FIG. 3.27 A UV map, texture art, and fi nal character created by Antony Ward.
all the categories, and most of the tools in the categories. Some of the tools require a more advanced model than would be productive to create for this section, so we’ll wait to cover them in detail in Chapter 13.