|01-26-11, 12:10 PM||#1|
Join Date: Jun 2009
How PhysX is used in Breach: Interview with Atomic Games
This week our undivided attention is focused PhysX SDK based multiplayer shooter Breach, notable for its pervasive and complex dynamic destruction system.
We've contacted Atomic Games, developers of Breach, to get more background on PhysX implementation and technical aspects of in-game physics. Mark Davidson, director of core technologies, was kind enought to answer some of our questions:
PhysXInfo.com: Destruction system and physics in general ' what do they mean for Breach ? Are they just a cosmetical features or integral part of the gameplay ?
Mark Davidson: Destruction in Breach defines the game. It's not just a facet of game play; it is the core mechanic, the soul. Everything revolves around it, how to attack, how to defend, where to take cover, these choices are all driven by the destructible nature of the environment.
The fact that almost anything on the battlefield can be destroyed means physics play a pivotal role in how any skirmish plays out. We have gone way beyond swapping models for a destroyed version, In Breach you are physically affecting elements of the world and forcing other players to react to that.
PhysXInfo.com: We know that Breach is using PhysX SDK ' why was it chosen as physics middleware ? Have you encountered any problems with PhysX during development ?
Mark: Atomic made the decision to use PhysX many years ago ' in fact, before Ageia were acquired by Nvidia. It's an extremely robust SDK and allows for a lot of developer customization, especially when it comes to making use of multiple processors or cores.
This was a necessity when developing on the 360, but it also translates well to multi-core PCs. Most of the problems we encountered in development were general resource and usage issues associated with unbounded destruction; the size of the world, the number of actively simulated objects, issues of objects stacking after collapses etc. These were issues Atomic needed to address internally.
PhysXInfo.com: How exactly PhysX SDK is being utilized ? is it responsible for collision detection, character controller or rigid body physics ?
Mark: It's used for much more than just collision and rigid body simulation. Almost everything in the environment is physically simulated, or at least is some kind of PhysX object. Explosive damage, shockwaves and ballistics are all calculated accurately and make extensive use of the library features. Keep in mind that we also have an active cover system that is available on almost everything in the play space, and this must also react to any destruction.
PhysXInfo.com: Are you using any modules from NVIDIA APEX Toolset, like APEX Destruction ? More advanced PhysX features like cloth, softbody or fluids ' are they supported ? Can physics simulation take advantage of additional CPU cores ?
Mark: We built our own destruction pipeline from scratch. This is a philosophical choice Atomic has made with respect to development. We believe by creating proprietary technologies that drive new play mechanics we can create the type of games that are not available anywhere else. However, there may be aspects of APEX that we use in the future.
Our simulation most certainly takes advantage of the available CPU's.
We really didn't make use of soft bodies, cloth or fluids mainly because the game play did not call for it. We wanted to direct all our effort, and horsepower, to solving the issues of destruction, and making the dynamic environment have a fundamental effect on the game play.
PhysXInfo.com: Will PC version of Breach include any enhancements over Xbox 360 one? What about GPU accelerated physics effects ?
Mark: On the PC version we offer the user a control panel for adjusting physics parameters. Here you have the ability to really crank up the effects and amount of simulation that can occur in the game. We decided to do this because of the vast performance differences you find on the PC platform over consoles, and we wanted the user to have the best possible experience available for their machine.
PhysXInfo.com: Is appropriate Nvidia GPU required to play Breach in all of its PhysX 'glory', or fast multi-core CPU can do the work too ?
Mark: You can still run lots of the physics on other video cards, but we've optimized our performance for Nvidia cards.
We remind you, that Breach will be released just in a few days, at January 26, for Xbox 360 XBLA (1200 MP) and PC (19.99 $).