JReality

Technical Problems Requiring Solution

1. Browser Configuration: While virtual reality browsers exist, most are implemented as plug-ins to Netscape and Internet Explorer, and most users are unwilling or unable to install such plug-ins.
2. Browser Performance: VRML files are typically large and processing is non-trivial, which result in substantial delays in both scene downloading and scene rendering.
3. Browser Navigation: Navigation in virtual 3D spaces is hard for the average user.
4. Cost of Content: 3D scene creation is much more difficult, time-consuming, and expensive than creation of textual and 2D graphical data.
5. Scene Connectivity: VRML hyperlinking results in a discontinuity and loss of the virtual reality feeling.

Technical Approach

1. Browser Configuration

While virtual reality browsers exist, most are implemented as plug-ins to Netscape and Internet Explorer, and most users are unwilling or unable to install such plug-ins.

The JReality CM Surveyor is a virtual reality browser written entirely in Java^TM using the new java3d API. In its applet form, it is automatically downloaded when a CM Surveyor-based VR web page is displayed. No installation or configuration is required on the part of the user or his ISP. Once downloaded, CM Surveyor remains in the browser's applet cache, and is not downloaded again when another CM Surveyor-based VR web page is encountered. Thus, subsequent VR web pages will display much more rapidly as long as the browser is not killed (and the cache cleared).

If desired, the user can explicitly download and install CM Surveyor with his browser configuration. This will enhance download performance by eliminating the need to download CM Surveyor the first time a CM Surveyor-based VR web page is displayed after restarting the browser.

2. Browser Performance

VRML files are typically large and processing is non-trivial, which result in substantial delays in both scene downloading and scene rendering.

• Download Performance

Unlike VRML-based web pages, CM Surveyor-based VR web pages are stored as serialized (compiled binary) Java^TM objects. The serialized Java^TM objects that define the VR scene are stored as compressed JAR (Java archive) files. Because they are compressed, CM Surveyor VR scenes download 2-5x faster than equivalent VRML files.

Unlike other VR scene technologies, CM Surveyor-based VR scenes are defined using JReality's "Compartmentalized Model" (CM) technology. CM is a state-of-the-art approach to 3D scene modeling that can reduce download time by a factor of 100-1000 for a complex VR model such as a ship, skyscraper, or large shopping mall.

If desired, Compartmentalized Models and JAR compression can be supplemented by download streaming technologies such as VRML Streaming or Streaming VR to obtain even greater improvements in download speed. Even without streaming, however, CM and JAR will make CM Surveyor-based 3D web pages download faster than today's current crop of gif-bloated 2D web pages.

• Rendering Performance

The same technologies that improve download performance also help enhance rendering performance.

Defining the scene as serialized Java^TM objects eliminates the overhead associated with parsing and interpreting a VRML data file. In effect, CM Surveyor-based VR scenes are stored as (smart responsive) executable code, not (dumb sluggish) data. Also, the java3d API has been optimized to enhance run-time performance.

By far the largest performance improvement is due to CM technology. CM greatly reduces the number of polygons to be rendered, resulting in a corresponding increase in display performance.

The CM Surveyor browser also helps enhance display performance with its tunable rendering features. The user can adjust both the fidelity of the rendered scene (lighting controls, behavior controls, etc.) and the dynamic rendering rate (frames per second) to conform to the speed of the host machine.

Finally, the use of Java^TM bodes well for performance in the long-term. Java's integral support for multi-threading will enable the CM Surveyor VR scene browser to take advantage of future multi-processor client systems with little or no recoding. C++-based VRML display engines will require substantial rewriting to take advantage of future multi-processor hardware.

3. Browser Navigation

Navigation in virtual 3D spaces is hard for the average user.

The CM Surveyor VR browser supports ease of navigation by displaying not only the usual VR scene view but also top, side, and front section views of the entire Compartmentalized Model. The section cuts are taken through the location of the scene viewer (avatar), and provide the user with a "bird's eye view" of his location in the virtual world. Navigation is a simple matter of moving the avatar from one location in the section views to another, much like moving your finger over the floor plan of a house. The compartment and view angle at which the avatar comes to rest becomes the new view displayed in the VR window.

The CM Surveyor browser also helps enhance ease of navigation with its tunable rendering feature. The user can adjust the dynamic rendering rate (frames per second) that governs the pace of rendering in the VR window as the avatar is being moved. On high performance systems, the VR scene will change in real time as the avatar is dragged from one location to another in the section views. On low performance systems, rendering the VR scene can be disabled until the avatar finally comes to rest in a new location in the section views.

Section-view navigation ensures the user always knows exactly where he is, and where he is going, even in the most complex VR scenes. Tunable rendering ensures he can get there quickly, even on low performance systems.

4. Cost of Content

3D scene creation is much more difficult, time-consuming, and expensive than creation of textual and 2D graphical data.

Using current graphical model creation technology, the cost of creating the 100's or 1000's of compartments in a large Compartmentalized Model is prohibitively expensive as each compartment needs to be individually created using manual manipulation of a CAD-type creation tool. Thus, complete VR models of the interior of large ships or buildings is almost never achieved.

The JReality CM Creator tool reduces the cost of creating arbitrarily large Compartmentalized Models to very reasonable levels. The cost of creating a large model such as a ship or skyscraper can be reduced by approximately 2 orders of magnitude (e.g., from $100,000 to $1,000).

Outfitting each of the compartments with furnishings, coloring, lighting, etc, now becomes the most time-consuming aspect of creating a complete VR CM. This cost is reduced to minimum possible levels by utilizing a library of 3D objects (such as furnishings) appropriate to the structure being modeled. These 3D objects are created only once, then reused throughout all compartments of the structure. Existing VR layout tools are to be evaluated to identify the most efficient for this type of work, and the best integrated into the design of the CM Creator.

5. Scene Connectivity

VRML hyperlinking results in a discontinuity and loss of the virtual reality feeling.

Section views of the entire virtual world are at low level of detail, leading to excellent cognitive continuity when navigating among compartments. The user always has a "bird's eye view" in one set of windows while experiencing the "you are there" VR view in the main display window. Hyperlinking from one compartment to another takes place automatically as the user moves the avatar symbol in the "bird's eye view" navigation windows.