Using PlayStation Express

Nichimen's PlayStation Express is designed to allow you to quickly and easily create 3D object and animation data, and port that data to the Sony PlayStation. You can preview attributed objects without animation, export TOD animations, or use the Action Editor and the Vector Editor to create MIME (multi-interpolation method) animations on the PlayStation.

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Overview

The PlayStation's MIME (Multi Interpolation MEthod) feature lets users develop a new type of game, capable of interactively displaying 3D character action in real time. This real time animation supports render attributes and deformations, a feature unprecedented in the gaming industry.

Computer graphics software (and character animation based on skin deformation in particular), typically uses sophisticated hierarchical data structures. In the past, game systems have typically been incapable or inefficient at handling such hierarchical structures. The relatively simple data structure developed for use in the PlayStation can represent both 3D objects and their associated animation data.

N-Geometry uses the concept of displacements to describe animation with skin deformation; displacements calculate the difference in position of vertices using vectors. Sony's MIME concept is based on a very similar idea, which make N-Geometry an ideal fit for development of 3D game models.

In addition to MIME animations, the PlayStation supports TOD animations. TOD animations support multiple objects and texture maps, but no displacements. They are ideal for generating game environments and animations for objects with "fixed" shapes.

Using the PC

Keyframe vs. Vector animation

Keyframes, while powerful and useful for generating computer animation, are intended to produce a fixed sequence animation; that is, the script is defined, and each time the script is executed, the same animation is produced. The intent of vector-based animation is to generate interactive 3D action, which requires a new way of thinking about what makes an "action."

In MIME, an action is represented by a combination of a base vector (similar to a base displacement) and one or more additional vectors (similar to relative displacements). For each vector, a wave is created, which controls interpolation between vectors. With this approach, poses can be separated from time.

In vector based animation, you have a base shape for the model and a target shape for the model; the curve data determines the transition between the two shapes. By changing the shape of the wave file, you can completely control the transition between the two states.

Creating Data for the PlayStation

Figure 1.1 N-Dynamics, N-Geometry, the Vector Editor, and PSX Express

Action is previewed in both the Dynamics playback window and PSX Express playback window, depending on the source of the recording.

• Objects to be animated are created in N-Geometry:


• For MIME objects, you define any displacements and Sony domain render attributes.

  
  

• For TOD objects, you define any Sony domain render attributes, including texture maps. TOD files are described later in this chapter, in the section "Attributed Objects and TOD Animations," on page 1-8.

• The object is animated using N-Dynamics.
• Animations can be previewed in the Dynamics Playback window.
• When the animation looks correct, the Vector Editor can be used to create a new MIME object out of the N-Geometry model, based on cues in the N-Dynamics script.
• The Action Editor creates a new action based on the MIME object created in the Vector Editor. The action consists of a series of subactions, each of which contains a vector (pose) and wave (curve data). The curve data in these subactions can be edited using N-Dynamics' extensive curve editing tools.
• Animations can be played back in real time, at variable speed, or in a loop (just as in N-Dynamics) in the PSX Express Playback window.

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MIME Objects

• Vector files
• Wave files

This data is written to the local hard drive or to a shared disk via NFS, then sent to the PSX development system via FTP.

Vector

Wave

Data Structure

Figure 1.2 Data structure of a MIME object

Each of these elements is described in the paragraphs below:

MIME Object

Geometry Object

Note. Currently, the PlayStation does not support objects with hierarchical data structures; objects to be animated as MIME objects must be terminal objects consisting of a single skin.

Vectors

• A base displacement, which is the initial state of the object for the vector. (This state corresponds to an absolute displacement in N-Geometry.)
• A list of relative displacements (and their applied values) for the object. These displacements correspond to relative or rotational displacements in N-Geometry. There is no limit to the number of displacements that can be used to create a given vector.
• A finalize vector, which lets you do any fine editing of shape deformations (such as the skin around an elbow) which is difficult to define using other functions. The finalize vector stores the relative value between the original shape and the shape after editing, which frees you from repeating fine tuning work after changing other parameters.
• A set of final coordinates, which stores the coordinate values resulting from the application of all parameters plus the finalize vector.

Action List

Each action consists of a base vector and zero or more optional subactions. An action requires both length (seconds) and rate (frames/sec) parameters, which can be changed at any time.

• The base vector is the initial state of the shape in MIME; any vector in the MIME object can be used as the base vector.
• Each subaction contains a vector and a wave.


• The vector can be any vector in the MIME object.

  
  

• The wave is not object dependent; you can use a wave associated with the current MIME object, or read a previously saved wave.

• The final vector corresponds to the last cue in the N-Dynamics script; usually the same as the base vector to create cyclical animation.

Waves

A .dat file is written when an action is saved. This is an action definition file which describes which vector is associated with which wave.

This is an user-editable ASCII file; if you wanted to modify which wave was associated with which vector, you could manually edit this file, rather than making the change from within PSX Express.

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Attributed Objects and TOD Animations

TOD animations are much simpler to create and send to the PlayStation; in fact, they can be sent using only N-Geometry and a simple N-Dynamics script. TOD animation is discussed in more detail in Chapter 2, "Objects and TOD Animations" .

Finally, you can preview your attributed objects on the PlayStation. Previewing objects can help you to optimize the appearance of your objects and textures for the PlayStation, streamlining the development process and saving time once you begin to animate your objects.

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Configuring N-Dynamics

To do so:

1. Open N-Dynamics.

2. (CLICK-L) on Options.

The N-Dynamics Options menu appears:

3. Specify the correct PC hostname.

If you don't know the name of the computer you need to be attached to, consult your System Administrator.

Copyright © 1996, Nichimen Graphics Corporation. All rights reserved.