3D in Photoshop CS4
- 3D Fundamentals
- 3D in Photoshop
- Creating 3D Content in Photoshop
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3D Fundamentals
Working with 3D content offers many benefits. Although learning the fundamentals of 3D workflow and design is a challenge, once you know the basics you can quickly use a mix of 3D models and 2D imagery (as backgrounds or textures) to build a scene inside Photoshop or your favored 3D application. One advantage to this is that you can quickly simulate a large array of lighting conditions, camera perspectives, and other photographic techniques that would take days of work in the field. Photoshop includes many improvements to 3D workflow, such as a more powerful rendering engine and the ability to create and manipulate various kinds of lights and materials.
Keep in mind that the 3D functionality in Photoshop is not meant to replace stand-alone 3D applications. Instead, Photoshop serves as a means of making 3D workflow more efficient and providing more creative options for artists and designers. Even so, the new 3D capabilities allow you to do much more directly in Photoshop than was previously possible. Ideally, this reduces time spent moving between applications making lighting or scene modifications and opens up new paths for producing more compelling artwork.
If you are new to the world of designing in three dimensions, this section provides an overview of 3D design fundamentals as they apply to Photoshop and other applications. If you are familiar with 3D workflow, you can jump ahead to the next section, which covers the new 3D capabilities that Photoshop offers.
Polygons. Most 3D models are made from many smaller, 2D polygons that are grouped together “edge to edge” to create the illusion that an object has volume and depth. The size, shape, and number of the polygons determine the level of detail in your model. It is not uncommon for even relatively simple models to have many thousands of polygons. The smaller the polygons (and the larger the polygon count), the more accurate and detailed your model will be.
You can’t do much to modify the properties of individual polygons in Photoshop (you will need a 3D application such as Strata or Cinema 4D for that), but you can affect the total polygon count. For a scene that is very detailed, expect a high polygon count. Having more polygons ultimately demands more memory and processor power; depending on how many viewports you have open, some areas on your model may not be visible onscreen. Some programs also give you the option of leaving hidden polygons unrendered as you work, which can save a lot of time.
Basic Terminology
Although it’s not possible to cover every important 3D concept in this book, you can use this sidebar as a simple glossary for understanding fundamental 3D concepts. Most of these terms relate to any 3D program you might need to use, not just Photoshop.
Aerial perspective. This is the atmospheric effect of distance on an image. This includes haze, light falloff, and loss of detail and saturation with increased distance.
Depth map. This is a translation of an image’s gray values into distance from a plane or surface. Typically white is the highest possible value (or altitude from the surface) and black is the lowest possible value, with intermediate gray values representing the distances between black and white.
Ground plane. This is the visual aid used by all 3D programs and Photoshop to provide a horizon reference and the ability to accurately judge vertical movement of a model.
Linear perspective. This is a simple perspective using converging lines to define the horizon and vanishing point. The Vanishing Point filter in Photoshop uses algorithms based on this perspective to generate its results.
Material. This is the general term given to all the textures, opacity, and other surface characteristics that define the appearance of a mesh in a 3D shape layer.
Mesh. This is a collection of adjoining polygons that define the shape or surface contours of a 3D model, including landscapes. For Photoshop, a model may consist of one or many meshes, which are often viewed as a wireframe-like structure. Because of a higher polygon count than a 3D shape layer, meshes in Photoshop often take longer to create, modify, and render.
Modeler. This is software that generates the illusion of a complex shape (such as a person) in three dimensions by combining numerous 3D primitives, and then using various shape modification tools to smooth the boundaries between them so that they look like a single, continuous shape. These representations of real-world or imagined objects are called models.
Object movement vs. camera movement. The 3D camera tools in Photoshop move the viewer “around” the object, while the object itself stays put relative to the document grid. Conversely, the 3D object tools move the actual object around the document grid, while the camera (or viewer) stays in place.
Primitive. This is a simple geometric shape with depth and volume. Made from small, 2D polygons, primitives are used as the building blocks for more complex shapes. Common examples include cubes, spheres, pyramids, cones, and cylinders.
Rendering. This is the process that gives a model a realistic appearance or, at a minimum, a smooth, continuous surface so that you can evaluate its shape, mold and edit your model, and apply textures to it. There are different “levels” of rendering quality; typically lower-quality (that is, low-resolution) renders are used when working on a scene or model, and high-resolution renders are used only at the end of the process because they can take quite a long time to finish.
Rotation. This is the ability to rotate a model, object, or camera around a specific axis.
Texture. In Photoshop, this is one of the component surface characteristics that defines the appearance of a material.
Viewport. This is the name often given to special windows inside a 3D program that display your model from different points of view (for example, a Top view or Front view). It is often possible (and useful) to have multiple viewports open at the same time when modeling. Figure 9.1 shows a rendered version of a wireframe model using multiple viewports in Maxon Cinema 4D.
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Figure 9.1 Viewports allow you to see models from multiple vantage points in 3D space.
Wireframe model. This is the most basic way to view any 3D model, showing only the outlines of the polygons that are used to create it. That is, a wireframe model has no surface characteristics; it is like a digital skeleton of the object you are creating (Figure 9.2).
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Figure 9.2 Wireframe model of a human-like shape. The model consists of many primitive shapes, which in turn are made from many small polygons connected together.
X axis. This is the horizontal reference axis in 3D space. Moving an object along this axis in a document will move it from left to right relative to the model’s Front view.
Y axis. This is the vertical reference axis in 3D space. Moving an object along this axis in a document will move it from top to bottom relative to the model’s Front view.
Z axis. This is the depth axis in 3D space. Moving an object along this axis in a document gives the illusion of moving from front to back relative to the model’s Front view. That is, it will appear to move closer to or farther away from the person viewing it by becoming respectively larger or smaller in scale as you move it.
Materials. Working with 3D involves not only building and positioning models but also controlling the surface characteristics of your model (Figure 9.3). Once you’ve built your model, you must add materials—to cover the lines and fill the gaps in the wireframe view of your model. These materials interact with light and the simulated environment to give the model a realistic appearance.
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Figure 9.3 These materials were created in just a few minutes using Cinema 4D’s Materials panel (bottom-left) and the Attributes panel (bottom-right). Each sphere in the Materials panel provides a preview for a different custom material.
Each material typically serves a unique purpose and can be combined in different ways with other materials to create a specific look. For example, to create a 3D model that appears to have human skin, you would need to define a specific material for each skin characteristic. Materials would need to be defined for the skin’s color, reflectivity, translucency, texture, and even contours (sometimes called a bump map), which are created by hair follicles, muscle tone, and the like. Similarly, if your model needed other human traits such as hair or sweat, you would need to generate materials for those as well. It is not unusual for a model to have dozens of materials defined for any surface type.
Lighting. Once you have defined your materials and applied them to specific regions of your model, you need to create a surrounding environment with which they can interact. As with photography, the most important part of any successful 3D design is the lighting. Lights are needed to define how the model is lit (obviously), as well as to define additional properties. As you might expect, 3D lights have many editable properties, such as color, focus, falloff, and the ability to cast shadows, based on the characteristics and position of your models.
However, lighting properties can come from multiple sources, not just from the lights you create. Some materials have properties that define whether they glow, reflect, or even self-illuminate! Lights can even be placed inside a model in some cases to create unique visual effects. The sobering part of all this creative freedom is that each characteristic of 3D light, each material, and each model has to be defined and controlled in software. Most 3D programs have many buttons, sliders, and menus to learn and keep track of! The new 3D panel in Photoshop (discussed later in the chapter and shown in Figure 9.4) is fortunately easier to learn but nonetheless a good example of the complexity behind 3D content.
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Figure 9.4 The new 3D panel in Photoshop allows you to manipulate a variety of texture and lighting properties for imported models and 3D shape layers.
Environment. The final building block of any 3D scene is its environment. A 3D model by itself is usually not very interesting, until you place it into a specific environment or context. An environment can contain a variety of lights, atmospheric effects, materials, and other items (sometimes unseen) that interact with the surface characteristics of your model to create the desired effect, such as a sparkle, a reflected color, or other “looks.” For many situations, an actual 2D photograph is used to create the “setting” for a 3D model, with 3D lights added into the mix to illuminate the model in ways that are consistent with the photo.
Many professional 3D applications—including Cinema 4D, profiled later in the chapter—let you simulate realistic 3D environments, including atmospheric effects and natural features such as clouds, bare earth, fluids, and foliage. Other programs are dedicated specifically to this purpose and can “grow” a terrain by using so-called organic terrain generators. 3D artists often use specialized applications, rather than a single program, to perform a specific task in their 3D workflow. This is facilitated through the use of common 3D file formats that allow the model and scene data to be exchanged between programs. These formats are discussed later in the chapter.
Rendering. As you work in a 3D program to create your content with models and environments, the view on the screen will usually be a low-resolution preview. Most 3D-capable programs provide preview options to ignore features such as shadows or complex material interactions so that your computer can quickly approximate the model’s appearance as you modify its shape and material properties. If you were to use the “final render quality” settings each time you previewed your model, the design process could take a very long time! For this reason, high-resolution render settings are typically used only at the end of the 3D content creation process.
Rendering takes your models, lights, materials, and environment in their current state and performs complex calculations on the entire scene to produce its final appearance. This means all the lights, materials, and other entities are interacting with each other visually, as they do in the real world. It also means any rough edges or “jaggies” are smoothed out completely. Most 3D programs offer several “quality levels” for the rendering process, allowing you to decide how detailed you want each render to be, based on where you are in the creative process. The highest-quality render settings take the longest but produce the most striking results when the image is exported to a flattened format.
As with scene generation, several programs are dedicated entirely to rendering, providing many creative options during this phase of image creation. Photoshop also has its own set of render options discussed later in the chapter (Figure 9.5).
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Figure 9.5 Photoshop CS4 Extended provides a new Render Settings dialog that offers options for defining the quality and style of your rendered objects or shapes.
Abilities and limitations. You can use Photoshop to import 3D models from other applications, edit model textures in a variety of ways, and create a basic lighting setup. You can also build primitive 3D shapes from 2D image files and position your shapes and models (or the cameras viewing them) in different ways. The latter is discussed in the next section.
For now, Photoshop does not allow you to directly modify the shape or arrangement of the primitives that make up your imported model, or edit any of the 3D properties beyond the ones provided in the 3D panel. This is best left to professional 3D applications, because most have a large array of shape modification tools that are not available in 2D image editors like Photoshop.