REAL PHYSICS IN NBA ELITE 11
Jul 30, 2010
Hello everyone,
My name is Geoff Harrower and I’m a Software Engineer working on EA Sports NBA ELITE 11. I’m very happy to have the opportunity to write a blog about the Real Physics engine we’ve developed this year. The term “Real Physics” can mean different things to different people, so my hope is that this blog gives you a very clear understanding of what we’re doing, why we’re doing it and ultimately what impact Real Physics will have on the game.
The physics in NBA ELITE 11 impacts several different areas of the game in very different ways. I’ll go into detail on each one separately.
No More Two Player Animations
The number one reason we wanted to move towards Real Physics was to eliminate the two player animations that were commonplace in NBA LIVE.
One of my biggest frustrations in playing last year’s game was how often you lost control over your player due to these two player animations.
Some common scenarios in NBA LIVE 10 include:
-when driving the lane you could get pulled into a two player dribble bump animation or a two player jostle animation
-when playing defense against someone you could get pulled into a beat animation through no fault of your own
-when playing defense you could get pulled into a dunk on animation before you had a chance to attempt a block
-when going up for a rebound you could get pulled into a two player animation where the player who would get the ball was already decided before the animation started
Although these animations looked really good while they were playing back, they did not respect your momentum on the court, did not respect user input and had a negative impact on the gameplay experience.
Our solution to this problem in NBA ELITE 11 was to remove all two player animations from the game completely, and replace them with systems that allowed the user full control over their character and where a physical simulation determined the outcome on the court.
Physical Defense
As soon you remove the two player animations from NBA LIVE, there is a very glaring hole in defense which makes it completely ineffective. It became clear that the gameplay engine was relying on the these two player animations to prevent the ball carrier from getting to the rim. We realized that we’d have to start from scratch and rebuild the defensive systems in the game from the ground up.
In order to accomplish this, we built a one on one mode for testing purposes. The goal was to make playing defense fun and effective when you were one on one with your opponent without taking away control from the ball carrier.
The first stage was to take a look at our collision system. Like many sports games it was built to keep players from passing through each other, and encouraged players to pass by each other when in collision.
Under the hood, there were collision cylinders anchored at the players position. Because of the shape, if the dribbler collided with the defender he would just slide around him. This made it pretty much impossible to stop the dribbler.
Our solution for NBA ELITE 11 was to completely change the collision system and introduce something that would allow the defender to stop the dribbler by positioning himself between his opponent and the basket.
I’ve been using an analogy to describe the changes which involves ping pong balls and a pop can.
Take two ping pong balls and put them on a table. Now move them around as if they were two players in the game, one on offense and one on defense. Try and stop the offensive ping pong ball from getting past the defensive one. Not so easy right? They just slide by each other.
Now replace the defensive ping pong ball with a pop can and do the same thing. It’s quite clear that with these collision shapes defense is much more effective.
Things are obviously much more complex in the game, but essentially we have built two “pop cans” for the defender which are positioned along the shoulders and hips respectively. The offensive player has a “ping pong ball” positioned at his chest and hips.
The result is a much more realistic and effective collision system built for playing defense. You really feel like you have a physical presence on the court and have the power to stop the dribbler dead in his tracks.
Locomotion
Effective physical play isn’t of any use if you don’t have enough control over your defensive player to stay between your man and the basket. That’s why we scrapped our old locomotion system and implemented something new that is driven entirely using physics.
What this means is that you’ll get a level of responsiveness like you’ve never experienced before in a basketball game. Because the player is a particle in our physics simulation with a mass and forces applied to him, what he does will always respect momentum and will have a very consistent feel. We’ve tuned the momentum to give you just the level of responsiveness you need to stay with your opponent if you concentrate and react quickly to what your opponent does.
The physics implementation also makes it easy to give different players a different feel based on their player ratings.
Steals, Block and Rebounds
As mentioned above, steals, blocks and rebounds were implemented (at least partially) using two player animations in last year’s version of NBA LIVE. In NBA ELITE 11 we leverage the physics system to give you something completely different.
The biggest difference is that we’re now layering dynamic, physics driven animations onto the player who’s performing these actions as opposed to playing a canned animation. This means that you can steal while you’re moving around (because the steal animation is layered only on the upper body), you can reach in a 360 degree volume around your player, and where your player is reaching to can change dynamically while the animations are playing back.
For steals, this means not losing control of your player while you perform the action. It also means we can use proper physics and collision detection to determine if you got the ball, what direction it will be deflected, and whether or not it was a foul. On offense, it means you really need to protect the ball at all times and position yourself accordingly if you don’t want to lose the ball.
For blocks and rebounds, it means the outcome is not determined before the animation is launched. Players can adjust mid air to counter a dunk adjust or react to a change in direction of the ball mid flight. The physics system also allows us to collide with players mid air and alter the outcome on the court dynamically based on the physics simulation. Bigger, stronger players will be less likely to get bumped off their flight path making them feel stronger in the game.
Releasing the ball to physics
In NBA ELITE 11 you’re going to see a lot more variety in what the ball does, and because so much of the game is simulated through physics you’ll get a much more emergent gameplay experience.
In previous years, when you were passing a ball you’d pick the reception animation first, and throw the ball to that animation. Passes were rarely deflected because the system for picking up a ball that had been released to physics wasn’t very reliable.
This year, the reception system has been overhauled with the goal of always being able to get to the ball in a realistic and responsive way. This will apply to passing/receiving, chasing down a loose ball and rebounding.
Because of this we are now free to release the ball into physics at any time, and the game will respond intelligently.
This means in NBA ELITE 11 you’ll see tips, deflections, missed rebounds, lost dribbles, dribbles bouncing off opponents if you don’t protect the ball. All of this simulated using real ball physics.
Opening up the gameplay this way has made things much more dynamic and unpredictable, just like real NBA basketball.
The Ugly Duckling
One thing I want to be very clear about is that we did not integrate Real Physics into NBA ELITE 11 as a gimmick or as eye candy. We were very deliberate about where we chose to apply physics and to what degree. Every step of the way our goal was to improve the gameplay experience and the feel of the game. At times our animation visual quality may have taken a slight hit in favor of a better feel or more dynamic response. This tradeoff is deliberate.
In a video, a two man mocap animation is always going to look better than a dynamic, physically driven animation because it can be presented in the exact same context in which it was captured. When things change and the situation is different every time, that’s where our system shines. Until you actually play the game and feel the controls and the way the game responds to physics you will not be able to appreciate the tradeoffs we’ve made.
My hope is that everyone who reads this blog will download the demo when it’s released and judge for themselves.
The Bottom Line
Integrating physics into NBA ELITE 11 has had a huge impact on the gameplay experience. The animation system is much more dynamic and responsive to both the physics system and the user’s input, defense has been made both fun and effective by giving control to the player and releasing the ball to physics has created a game with emergent behavior where anything can happen.
This combined with our new controls and the countless additional gameplay improvements the team has worked so hard on this year makes NBA ELITE 11 the most realistic, dynamic and responsive basketball game I have ever played.
And it’s really, really fun.
Source -
NBA Elite 11 Blog