[Havok, long known for physics, now has a reach that extends into other crucial middleware areas. In this sponsored feature that's part of the Intel Visual Computing section, the company's Jeff Yates speaks about the present and the future.] 

For many gamers and developers, the name Havok is synonymous with physics. Havok's current physics SDK has shipped in some 200 games, including popular titles such as the Halo series, and Guitar Hero III.

For the past three years, the company has also been developing middleware and tools for game characters. Havok calls these products Havok Animation and Havok Behavior. To help deliver character assets into the cross-platform file formats used by these tools, Havok has also developed the Havok Content Tools, which are a set of plug-ins and exporters for Autodesk's Maya and 3ds Max, and XSI.

Using traditional 3D character animations, along with various procedural and blending techniques, these tools improve the fundamental interactions and low-level decisions that are crucial in helping bring in-game characters to life. Much of the intent behind these tools is to provide a back-end that is not only powerful but also comprehensible -- even to members of development teams who may not have highly technical backgrounds.

Havok's Jeff Yates has 15 years of experience managing the development of content creation tools, such as Autodesk's 3ds Max and Maya. As vice president of product management at Havok, he deals directly with clients who have specific requirements and serves as the company's public face for high-level product strategy.

We caught up with Jeff to discuss Havok's expansion into areas beyond physics, Havok's underlying goals for middleware tools, game development's focus on characters, and what he sees for the future of animation and behavior technology.

Havok is mainly known for its physics, but your animation and behavior components have been in development for a few years now, right?

Jeff: Yes. We had the coming-out launch of our animation product, Havok Animation, at Game Developers Conference (GDC) 2005. Since then we have continued to mature the product, and it is now in use in dozens of games. We've developed a complete content pipeline to help game developers get the animation assets in the game as effectively as possible.

For example, to deal with the natural memory limitations on many game systems, Havok Content Tools gather all the animation tracks in 3ds Max, Maya, and XSI, and compress them in a way that can be efficiently decompressed on a range of game consoles from the PS3 to the Wii. Compressing animation is a bit like compressing video: it relies on clever off-line analysis and packing that enables fast and relatively high-quality decompression in the game.

These compression settings are all controllable and previewable via the Havok Content Tools that install directly into popular 3D modeling tools. So you can get a sense of how much compression you are getting up front.

Havok Animation also offers various inverse kinematics (IK) solvers, with runtimes appropriate for game engines., We have Foot IK, which can adjust and climb over uneven terrain, as well as Hand IK, which can dynamically assess specific grab orientations for properly picking up objects and holding onto environmental elements.

Then there's what we call ragdoll mapping, which is basically runtime motion mapping between a simplified physical representation of the character, and its traditional "rig" or skeleton. For example, say you have a simple ragdoll specification with only a few spine bones (not a ton, because you don't need them for the physics), and also the higher-resolution bone system -- between 50 and 100 bones -- which is what animators usually work with.

With real-time ragdoll mapping, we can let the physics drive the animation, the animation drive the physics, or some combination of the two. We do this to achieve full-body IK-like effects -- with the added benefit that limbs do not pass through themselves or the body, nor through any other objects they interact with. It's the best of both worlds.

Are those animation features separable from the physics component?

Jeff: Yes -- Havok Animation is very modular and so things like the compression and decompression can be used by themselves as desired.

The IK is also independent. It's incorporated into the SDK structure in a way that is relevant for games, and it takes advantage of the underlying physics system to sense the environment and help make decisions. For example, consider what should happen to a character when one of its legs steps over a ledge. Should it strike an off balance pose, or transition into a falling state where it fl ails and grabs for targets, before hitting the ground below?

The Foot and Hand IK systems are equipped with all the bells and whistles to deal with these situations. And yet these systems can be used independent of physics if you like. But the physics gives the ability to make more informed decisions that make the animation look that much more convincing.

So how do you decide what development issues to move into outside of your core area of physics?

Jeff: That is a great question. You know, a lot of it is deep soul-searching. [laughs]

At Havok, we try to extend from our areas of strength, from the core competencies that we already have. We would not want to jump into an adjunct area where we are totally green. We grew into animation through our demos, because people would say, "Well, you guys say you can blend animations and physics, but show us."

In our demo creations, we began to notice that what we were writing was beginning to look more and more like a product. So we decided to build and support a full animation system and tool chain that people could license separately or with Havok Physics -- that's Havok Animation.