Pushing Vertices
A mesh consists of a set of vertices that are connected by edges. Edges connect to each other to form either three- or four-sided faces. (Chapter 4 covers this in more detail, along with how to work with each of these mesh building blocks.) When you tab into Edit mode on a mesh, you can manipulate that mesh's vertices (or edges or faces) with the same basic grab (G), rotate (R), and scale (S) tools that work on all objects, as well as the very handy extrude (E) function. These actions form the basis for 3D modeling, so much so that some modelers like to refer to themselves as vert pushers because sometimes it seems that all they do is move little points around on a screen until things look right.
Of course, modeling has more to it. You actually have a choice between two primary methodologies when it comes to modeling:
- Box modeling: As its name indicates, box modeling starts with a rough shape — typically a box or cube. By adding edges and moving them around, the artist forms that rough shape into the desired model. Bit by bit, you refine the model, adding more and more detail with each pass. This technique tends to appeal to people with a background in sculpture because the processes are similar. They're both primarily subtractive in nature because you start with a rough shape and bring about more detail by cutting into it and reducing that shape's volume. If you need to add more volume to the mesh outside of the initial box shape, you select a set of edges or faces and extrude them out or pull them out. If you need to bring part of the mesh in from the initial box shape, you select those edges or faces and either extrude inward or just pull them in. Box modeling is a great way to get started in modeling, but you run a danger of ending up with really blocky models if you aren't careful about how you move your edges around.
- Point-for-point modeling: Point-for-point modeling consists of deliberately placing each and every vertex that comprises the model and creating the edges and faces that connect these vertices. The process is actually not as bad as it sounds. You can think about point-for-point modeling like drawing in three dimensions. And as you may expect, this technique appeals to people who come from a drawing background (or control freaks like me!). The advantage of this method is that you can control the final look of your model, and you're less inclined to end up with a boxy shape. However, some beginner modelers fall into the trap of getting too detailed too quickly with this technique, so you have to be careful.
Figure 5-1 shows the difference between a rough human head created by using box modeling techniques versus using a point-for-point method.
Although many modelers have a preference for one methodology over the other, most agree that each method has its advantages and often modelers take a hybrid approach. They may use a point-for-point technique to rough out the model and then make refinements by box modeling. With the advent of 3D sculpting, which I cover in the “Sculpting Multiresolution Meshes” section later in this chapter, this way of working has become even more popular.
Adding background images in the 3D View
When working with meshes or any other type of 3D object in Blender, reference images are often helpful for getting proper proportions and scale. If you have a separate monitor, you can choose to display your references there. However, you can use a reference more directly by loading an image into the background of the 3D View. To do so, go to the 3D View's Properties region (N) and look for the Background Images panel. Left-click the check box next to this heading and expand the panel by left-clicking the triangle to its left. You see an Add Image button. Left-click the Add Image button, and you get a panel for managing a background image. By default, your image (after you choose it) displays on all orthographic views in the 3D View. You can narrow this scope by using the Axis drop-down menu. For example, if you're modeling a person's face and have a profile photograph, then showing that background image in the front or top views isn't useful, so you can use the Axis drop-down menu to just display the photo when you're looking from the right or left side view.
To pick an image for displaying in the 3D View, left-click the triangular icon to the left of the text that reads Not Set. Left-clicking that icon reveals an image datablock. Left-click the Open button, and Blender provides you with a File Browser for picking an image on your hard drive. When it's loaded, you can adjust the transparency, size, and positioning of your image. From here, you can continue to work, or you can add more images to display from other orthographic angles in the 3D View. People who model faces like to split the 3D View vertically, showing the front view in one 3D View and the right or left side view on the other. With reference photos of the same size set to display from the proper axis, it makes the process of modeling very speedy.
Figure 5-1: Box modeling (left) and point-for-point modeling (right) a simple human head.
