Overview of Flash 3D - Page 2

General Overview of 3D Topics

From fine art still images to title sequences for TV news to electronic actors in films, 3D tools are used everywhere in our media-saturated world. The range of tools is unbelievably large, too, from freeware desktop applications to high-performance, multiprocessor, dedicated machines on a network that do nothing but render frames of animation, day and night.

Although it does take a long time to find your voice in 3D and learn one of the incredibly complex (and expensive) software packages, there are some basic concepts that tie together all tools, goals, and areas of 3D.

Note: The concept of materials and textures is conspicuously missing from our roundup of general 3D subjects. This is because it is currently not practical to render textures to a 3D object in SWF vectors. Besides, the general lack of tools that will render textured 3D models to SWF vectors, the file size, and the complexity of such an SWF would prohibit its practical use.

Modeling

Modeling is the electronic equivalent of sculpture. This is the area of 3D that makes celebrities of good 3D artists (within 3D communities, anyway). The idea is that you start with a shape— usually a simple 3D object like a cube— and manipulate the vertices of that object to create a new shape.

If you haven't ventured into 3D before, you may wonder how you can effectively manipulate the appearance of a geometric shape like a sphere by its individual vertices, since a sphere is by definition an infinite number of points equidistant from the center. This leads us to the one central verity that underlies all work in all areas of 3D: models are made of polygons.

3D objects are typically made up of lots of little polygons, which are subdivided diagonally. We are not going to worry about the diagonals in this chapter. You can see how the sphere in the following image is not really a perfect sphere, but a sphere- shaped group of rectangles.

The array of techniques for manipulating these polygons is deep and wide. Some techniques are generally preferred for particular applications, such as low-polygon modeling by manually adding, subtracting, and moving vertices in a model with as few polygons as possible. This technique is preferred for artists who make models for 3D video games and other real-time rendering applications, because models with fewer polygons will take less brainpower for the game processor to render.

Other divergent methods of modeling are popular for different reasons, not the least of which are personal preference and artistic style. One family of modeling styles uses tangent handles to create 3D Bézier curves, which can give an object with few Bézier vertices a smooth, organic look. There are also tools- based approaches that deform the mesh of polygons for you based on parametric input, but these are a little outside the territory of hard-core 3D modeling. If you are interested in 3D, you could easily spend a month of focused, full-time study on the fine art of working directly on the polygon mesh to create models.

Another aspect of 3D that you should be aware of (though it will not be covered in this chapter) involves boning and skinning a model. This isn't as gruesome as it sounds. Boning a character is the process of building a skeleton for a model by drawing bones inside the character, while skinning is the process of attaching those bones to the mesh that makes up the model. You can even compose logic for the bones, giving them individual ranges of motion and particular bones that control others in a group— just like a real skeleton— using a technique and tool named, in 18th- century-birth-of-science fashion, inverse kinematics.

Animation

Any true Flash enthusiast will want to make a 3D model move. The particular workflow outlined in this chapter is limited to keyframes and tweening— just like those concepts work in Flash— because models will be built in one package and exported to another in a file format that does not support animation.

The larger world of 3D, by contrast, is anything but limited when it comes to animation. In addition to the control you gain over animated characters with a complex system of bones and skin, most packages have whole applications dedicated to the parametric manipulation of every aspect of animation. Most full-blown 3D packages have an electronic version of every camera and lighting apparatus used in cinema, plus some that exist only in the electronic world.

Rendering

All the parameters you define within a 3D model or scene, including the vertices of every polygon, the type, placement, and characteristics of lights, and so on, are all composed in the interest of generating visual output. Generating that output is called rendering, and it is a distinct interest in itself. We will be using Swift 3D to render our models and animations to SWF vectors, which means that the options for which details to render, as well as lighting, quality, and format options are much more limited than if we were rendering for video or still images. The process of rendering in Swift 3D is set in motion when you select File | Export.

Macromedia Flash 5 Developer's Guide
Tools - Page 3