Interview: Gabe Newell of Valve Software
With the announcement that Half-Life 2 will be available September 30, 2003, we took the time to speak with Valve Software’s own Gabe Newell. “Recently we were afforded the privilege of speaking with Gabe Newell, Valve Software’s Managing Director and head of the Half Life 2 project. We fired off a few quick questions to him concerning Source, the engine powering Half Life 2, and what we can expect from it.
Gamingnext – After all of the movies, both engine/tech oriented and pure gameplay, that came from E3 it’s safe to say that all of the gaming world is now clamoring for Half-Life 2. Can you tell us a bit about the technology used to power HL2?
Gabe Newell – I did a presentation on the engine for Vivendi a little while back. It was about 100 pages long, and we got through it in about 4 hours. I’m not sure really how to condense that all down, but I’ll try. We usually break it down into humans, graphics, interactivity, and AI. Now obviously there’s overlap. For example there’s a special shader for people’s teeth. That could go in the graphics section or the humans section. There’s a lot of intelligence in moving creatures over an LOD mesh – so is that AI, interactivity, or graphics? You get the idea.
For humans we wanted to make them look realistic and look consistent. Consistency is an important characteristic, as you need to make their skin tones look as “”realistic”” as their walk cycle. If something is too good, it actually breaks the illusion of humaness you’re trying to create. There are lots and lots of details that go into their skinning and muscles to make it look right. We probably spent more time on their eyes than anything else – for example you have to model them as ellipsoids rather than spheres to make them look right as they rotate within the eye socket. The facial expression system is pretty cool in a lot of ways, not the least of which is that it blends together multiple inputs yet always maintains consistency with a set of rules about what are valid potential facial states. In other words you can push random numbers through the expression system and you won’t get a face that a human can’t create and you will get believable transitions between them.
On the graphics side, there’s one issue that hasn’t really been discussed much which is scalability. When John Carmack and Michael Abrash created the Quake 1 engine, the fundamental problem was achieving an absolute performance level. When they set out to build an engine that would run a 3D software renderer at 15 FPS on their target CPU, no one in the world thought they could do it. As is typical with those guys, they showed everybody that they were wrong. They had a secondary problem which was optimizing for consistent framerates – it was more important to run 15 FPS all the time than it was to run 20 FPS until you had a dynamic light when it slow down to 5 FPS. Nowadays the problem is scalability. The difference between high end and low end hardware is getting wider. And the differences don’t necessarily correlate – so that something which has twice the triangle throughput may not have twice the memory bandwidth. A lot of the tricky work in Source is getting it to work across a wide variety of scenes (indoor, urban, outdoor) and across a wide variety of hardware. Not only do you have to run acceptably fast on a TNT or an Intel 810 based PC, but you have to fully exploit the capabilities of the current and next generation high-end cards. Physics is sort of the high-sex appeal feature for interactivity, so we tend to talk about that, but there are a lot of other things you have to do. For example there are things we use called “soundscapes” that use the player’s actions to drive a bunch of the ambient audio and musical events. Most people won’t notice it, but it makes the world seem more reactive in the same way that a good movie score makes the movie seem scarier or more dramatic.
Gamingnext – How can the Source engine handle both indoor and outdoor environments so well?
Gabe Newell – A lot of the flexibility in the engine involves making sure you are using the triangle and memory bandwidth you’ve got to render what’s most important in the scene.
Gamingnext – Half-Life was renowned for the enemy AI. What kind of improvements have been made for Half-Life 2?
Gabe Newell – A big push for us was making the AI more context aware. They needed to be a lot more aware of the player’s intentions, they needed to be a lot more aware of the world, and they needed to understand physics in terms of their path finding, and as a source of weapons (in other words “”I can smash this to get through”” or “”I can break something so something else falls on your head).
Gamingnext – How will Steam integrate with Half-Life 2?
Gabe Newell – Half-Life 2 will be available via Steam.
Gamingnext – Do you plan on leasing Half-Life 2’s engine and, if so, do you have anyone claiming interest yet?
Gabe Newell – Right now we are working with Troika to use Source as part of Vampire: Masquerade. We were big fans of Tim, Jason, and Leonard’s work in the past (Fallout, …), so we were excited to work with them as the first external group to use the new engine.
Gamingnext – How does the Valve Anti-Cheat technology tie in with Half-Life 2?
Gabe Newell – It will be part of the multiplayer components.
Gamingnext – What are the limits of this engine? Does it have boundaries or can it be implemented across a wide variety of game genres? (ex. Flight sim, RPG)
Gabe Newell – We’re really curious to see what the MOD guys come up with. Personally I’d like to see people try to do a networked fighting game.
Gamingnext – Will all the characters be able to implement as realistic expressions as the G-Man so brilliantly does or will it be toned down a bit to improve frame rate and game play?
Gabe Newell – All the characters are equally expressive. It’s not really a framerate issue.
Gamingnext – With the outstanding graphics that HL2 is using, what should gamers have, minimally, to run this game?
Gabe Newell – An 800 MHz P-III and a DX6 level hardware accelerator (e.g. TNT).
Gamingnext – Finally, how user friendly is this engine and will modders be able to create unique environments and maps that made the first Half-Life last so long?
Gabe Newell – We learned a lot through our experiences with TFC, Counter-Strike, Day of Defeat, and so on. This engine is much more MOD’able (if that’s a word) than Half-Life 1 was, and the tool set has been improved a lot. We’ll also be releasing a bunch of material to help MOD teams get their existing work up and running on the new engine as a starting point.
Gamingnext – Mr. Newell, our thanks for your time.