Sound Advice: Aureal3d An Interview with Skip McIlvaine, Developer Relations Manager, Aureal Inc.
	Q: In comparison, what is EAX and what does it accomplish? EAX is an extension to DirectSound3D which allows a developer to choose from a number of reverb sound effect presets that trigger when the gamer enters a specifically sized room or environment. Q: Does EAX have any advantages over A3d? I think most would say that EAX is easier and faster to implement. Now, we would say that comes with the burden of hand-tweaking each room in a game and difficult forward maintenance as level designs or game requirements change. Additionally, we've done quite a bit to make A3D 2.0 easier to implement -- cleaned up the interface, introduced tools, etc. The other advantage that's been talked about is that EAX is good for providing a "feeling" or experience in games, whereas A3D is a physical model -- which isn't always best to achieve a dramatic effect. We would argue that it's always best to start with reality and tweak from there to achieve your intended experience. Quake III's graphic engine is based on visual reality, but level designers play with lights and dramatic texturing to achieve a certain mood on each level, but you wouldn't see those things in real life. Q: Creative Labs objects that wave-tracing is hard to implement. Can you enlighten us? Certainly Wavetracing is a more ambitious, innovative and realistic technology than EAX, and as such has a lot more complex things going on "behind the scenes." What's cool is that Aureal has done most of the work up front and the complex things are already done for them. While complete control over everything is given to the developer to craft a more realistic, high-performance audio experience, A3D 2.0 provides intuitive controls and tools to make implementation easy. While setting up Wavetracing requires a little work on the part of the developer, the effect is greater than EAX and the developer does not have to step through every single room to select a reverb preset (which can be an extremely tedious task). Once implemented, Wavetracing takes in the entire geometry engine and renders its effects on all environments, whether they are added before or after the Wavetracing implementation. As easy and straight-forward as A3D 2.0 and Wavetracing are now, Aureal has tools and Plug-Ins in development that will make implementation of Wavetracing as simple as a click of a button! What could be easier than that? Q: What are the advantages of wave-tracing over a reverb technology like EAX? Wavetracing is the realistic acoustic modeling of the geometry of an environment. EAX is simply a static reverb technology configured through the selection of a limited number of presets. Developers who use Wavetracing simply pass their existing graphics geometry to the A3D 2.0 engine and it does all the work. As Aureal spent a lot of time up front developing this very complex technology, the developer is spared having to recreate their environments for the less realistic effect of EAX. Wavetracing currently has two major functions: - to trace and render the reflections of sound waves as they bounce off of walls, surfaces, and other objects; sound waves are absorbed or reflected according to the material of the objects that reflect them - to trace the paths of sound waves and render the effects created when these sound waves are blocked and absorbed by walls, surfaces, and other objects; occluded sound waves are muffled and quieted according to the material of the objects that block them. The ultimate goal of Wavetracing is to give game developers a tool that is simple and easy to use that let's them make games with immersive, high quality audio landscapes. With this goal in mind, Aureal spent years working with game developers to design the A3D 2.0 Wavetracing engine. As a result, we have an API that is easy to use and based on the OpenGL technology they are already familiar with. We have automated most of the Wavetracing features so that once developers add it to their game engines, all existing levels and all new levels automatically take advantage of Wavetracing. We've even added functionality to let A3D 2.0 itself determine what it can do on any given platform. Old ISA cards will use a software-based effect with occlusions, while A3D cards deliver the full Wavetracing experience - all with no extra work from the developer. With plans to make A3D cross-platform, developers won't even have to worry about supporting multiple operating systems. Click to continue		EAX, on the other hand, is a knob that forces developers to determine what reverb they need to use. It requires them to modify existing levels to mark reverb sections. This often causes titles to be released where companies did not have time to mark all their levels with reverb, to use a single reverb in all places, or to only mark parts of levels with reverb. For gamers, this is a situation Aureal decided to avoid at all costs. Being an extension of DirectSound, EAX also does not have the flexibility A3D does to add new features based on developer demand. A good example of this is how the latest version of EAX supports occlusions, but they are not automated. It is up to the developers to decide which sources are occluded and which are not. A3D is designed to bring today's best audio technology to developers with the least amount of work while having the ability to automatically support tomorrows new technologies. EAX is a DirectSound extension that also gives direct access to new technologies but lacks the automation of Wavetracing. EAX is simply a "wow effect." Wavetracing is a natural way to model a 3D space for audio and do so realistically and more convincingly for the end-user; it is also the best way to provide the most full-featured audio for the broadest audience and with the least amount of work and compatibility concerns. Q: Creative Labs has argued that CPU cycles will be eaten by wave-tracing implementation. Can you give us some actual in game figures? In the first implementations of Aureal Wavetracing, in games like Half-Life, a less than optimal approach was taken, and there are some CPU cycles used. What these numbers are depends on a lot of things: CPU speed, driver version, environment complexity, number of sound sources playing, etc. Future implementations of Wavetracing in games and future drivers from Aureal will reduce the cycles spent by the CPU to close to 0. The majority of processing is done in our hardware, and in the case of non-Aureal hardware, the functionality and quality of rendering will be scaled back to keep this number close to 0 on any card. We aim to make this a non-issue in future drivers and games; new releases by Aureal, and A3D 2.0 developers, will make this clear very soon. Q: Some time after A3D implemented sound occlusion (like sound behind a wall), Creative labs followed suit. Why is EAX the follower and not the creative leader in areas like this? Aureal and A3D were created by ambitious technologists with nothing to lose. Aureal is an innovator and is focused on audio only. Creative had established a decade-long standard that they did not have to improve upon to make money. Without competition, innovation stalled and Creative sat pretty in what amounted to a virtual monopoly. They had everything to lose by changing the standard. They simply got complacent and rested on their past accomplishments. They then moved onto multimedia kits, video cards, DVD drives, etc. Their focus on audio was gone. It was the perfect time for a forward-looking AUDIO company to step in and advance the state of audio on the PC. This scenario recurs throughout all industries and will continue to happen until the end of time. It's nothing new and it certainly won't be the last time it happens. Aureal intends to stay on the cutting-edge of audio technology and quality with an intense focus on changing trends and needs...oh yes, and on audio only. Go to Page Three
Copyright © 1997 - 2000 COMBATSIM.COM, INC. All Rights Reserved. Last Updated June 19th, 1999