Metro: Last Light, sequel to Metro 2033 title, is aiming technology throne with DX 11, tesselation and support for GPU accelerated PhysX effects. PCGamesHardware.com had the chance to talk with Oles Shishkovtsov, Chief Technology Officer at 4A Games, about improvements that are planned for PC version of the game.

PC Games Hardware: You keep the support for GPU PhysX in Metro Last Light. If so can we expect some improvements or enhancements compared to Metro 2033 (e.g. soft bodies, debris, and destructible environments)? What graphics card do you recommend for maxed details in Full HD with Antialiasing? An upcoming Nvidia Kepler-based Geforce for example?

Oles Shishkovtsov: Yes, you can expect a lot of improvements, especially in destruction and debris. The upcoming Geforce cards will be fully supported.

PC Games Hardware: When benchmarking Metro 2033 we found out that the engine utilized more than four cores of multicore CPUs if we were using the advanced PhysX effects on CPU, so you are utilizing Nvidias PhysX SDK 3.x? Will all the advanced PhysX effects only be available in PC version?

Oles Shishkovtsov: That’s the common misconception that PhysX 2.X cannot be multithreaded. Actually it is internally designed to be multithreaded! The only thing – it takes some programmer time to enable that multi-threading (actually task generation), mostly to integrate with engine task-model and ensure proper load-balancing. So, 2033 used PhysX 2.8.3, and Last Light uses similar, a slightly modified version at the time of writing. And yes, advanced PhysX effects will be available only on PC.

Read the full interview

Sounds good.

However, we are hoping that this time Metro will be able to surprise us with more than two minor particle effects (as in Metro 2033 – while “debris, smoke and dust” were promised) and it won’t require “upcoming GeForce card” to run those GPU PhysX effects with playble framerate.

Almost four years has passed since NVIDIA aquired Ageia and presented their version of hardware accelerated PhysX Technology. However, anyone who is watching GPU PhysX progress closely can say, that so far it has not shown any significant advancement – but is the fight already lost or is it just taking time to harness up, but will ride fast?

We got a chance to chat with Tony Tamasi, Senior Vice President of Content & Technology in NVIDIA, Ashu Rege, Vice President of Content & Technology, and Rev Lebaredian, Director of Engineering, to clear up these questions, and recieve some insider information on future development plans for PhysX SDK and NVIDIA APEX toolset.

PhysXInfo.com: Over last years, amount of GPU PhysX games is actually decreasing. There were five games in 2009, three in 2010 and so far only one in 2011. How can you explain that?

Tony Tamasi: It was a choice on our part. We had a large amount of resources we could otherwise dedicate to content, but we needed to advance the core technology. We needed to get PhysX 3 done, and we needed to get APEX done to the degree where it is usable by game developers. We had to put a lot of resources there, which meant that some of those resources weren’t directly working on games.

But in the long term, game developers can actually use PhysX and APEX, and make use of the GPU without significant amounts of effort, so that a year or two years from now more games will come out using GPU physics.

Alice: Madness Returns - most recent GPU PhysX title

Rev Lebaredian: When we initially acquired Ageia, we made a big effort to move many games over to GPU PhysX. We learned a lot in that period of time: getting GPU physics into games, what are the problems, what works and what doesn’t. That gave us the opportunity to regroup, refocus, and figure out how to do it correctly.

We made a conscious decision. After we did a bunch of PhysX and APEX games in 2009 and early 2010, we said “Ok, we have learned enough, we need to sit down and focus on finishing APEX and changing it based on what we just learned, as well as PhysX 3”. Doing as many titles as we were doing before was just going to slow us down.

It made more sense to slow down the content pipeline but get the tools right, but that puts us in the position when once those are complete, it is actually less work for us to get PhysX in games.

This slowdown has not been because of any problems. It is something that we have decided to do.

PhysXInfo.com: So NVIDIA APEX is supposed to give developers the tools for easy creation on physical content in games, and you will receive GPU PhysX support as a byproduct. Is this idea working already?

Rev Lebaredian: It won’t be 100% free. Anytime you’re going to change the quality of something, you’re going to have the artists and level designers do a little bit of work to tweak it so it will look right.

Sure, let’s say if you have clothing you can just increase the number of vertices or increase the number of bodies for something with destruction, but most likely they going to want to tune it at different levels.

What we are trying to do with APEX is minimize that work. If you spend 10 hours putting together a set of assets for consoles, it shouldn’t take you another 10 hours to do the GPU stuff, maybe an additional half hour—depending on the developers and game in question obviously.

Tony Tamasi: And  I can actually tell you for sure, when we first started on the GPU PhysX effort, it often took more time to do the GPU physics work than core physics work, which is not the right balance. So we have to get the balance to make it incremental effort.

Ashu Rege: If you compare some games with APEX and GPU PhysX from one or two years ago, with some other games we are working on today, we have improved by 4-5 times in terms of less man-hours of work to get GPU PhysX done.

PhysXInfo.com: So how many GPU PhysX games are we going to see in upcoming years?

Rev Lebaredian: I think you’ll see more GPU PhysX games next year than you did this year, and I would expect to see a lot more in 2013. PhysX 3 and APEX are now just getting integrated–that’s why you see that kind of lag.

Tony Tamasi: We’ve also taken steps to integrate it [APEX/GPU PhysX] in major engines, like UE3—that enables a lot more developers to be able to use it out of the box now. When we did the GPU titles in 2009, essentially we have to do that integration each time. So there should be a large increase in GPU physics content just because it’s easier.

PhysXInfo.com: And for how long are you planning to further develop and use PhysX Technology?

Tony Tamasi: As long as we can see!

Ashu Rege: The interesting thing is that we haven’t even touched, frankly, the surface of the cool new things that can be done in many directions; things like heightfield fluid simulation, better cloth–I mean, there are so many different improvements, for both algorithms and technology as well as improvement for the tools so developers can integrate these features much faster.

So yes, we keep working.

PhysXInfo.com: Is the fact that GPU PhysX is exclusive to NVIDIA some kind of barrier for GPU PhysX adoption?

Rev Lebaredian: It is not a secret that most of game developers are concerned about consoles. PC for them is a smaller SKU usually, so PhysX not running on competitor GPUs  does not really matter that much to them.

Tony Tamasi: For every title we have worked on; for every one that I’m aware, that was never a reason for someone to use or not to use GPU PhysX.

PhysXInfo.com: Do you have any plans to port GPU PhysX to DX11 (Direct Compute) or OpenCL?

Rev Lebaredian: No plans to do it. Maybe if there will be a good reason for that in the future, but there is no current plan.

PhysXInfo.com: So developers are not asking you to port GPU PhysX to OpenCL?

Tony Tamasi: Nope.

Rev Lebaredian: No.

PhysXInfo.com: Are GPU PhysX effects going to be friendlier to multi-core CPUs in the future?

Tony Tamasi: You can use multi-core CPUs in PhysX 2.8, but it requires a lot of extra work to do that.  In PhysX 3 most solvers are parallelized across as many threads as are available.

Rev Lebaredian: It is usually not possible to get linear scaling with increasing numbers of CPU cores automatically. It is not reasonable to expect that if you’ll throw 8 cores at it, it will be 8 times faster.  However, we’ve done a lot of work in PhysX 3 to maximize usage of multiple CPU cores whenever possible.

PhysXInfo.com: What do you think about Hybrid PhysX? Isn’t it for good?

Rev Lebaredian: Good at what cost?

Supporting it would be a huge amount of QA for us, and it would be weird too – if we’ll find a bug in AMD’s drivers, what will we do?

Ashu Rege: For the foreseeable future we will not supporting it officially. If it works- it works, if some guys can figure out how to make it work – great for them.

After discussion of common topics, we have moved to more specific questions regarding PhysX SDK and NVIDIA APEX toolset.

PhysXInfo.com: New PhysX SDK 3. Has it already equals the hopes or was it waste of time, which has created more problems that it has solved?

Tony Tamasi: As far as I can tell, every developer we talked to is happy with it.

Rev Lebaredian: We have had developers demand to use it over 2.8, and that’s actually accelerated our plans for getting APEX working with it.

PhyXInfo.com: So developers now prefer PhysX 3 over 2.8?

Rev Lebaredian: Yes.

Ashu Rege: We build it to satisfy all their needs, so it would be really strange if they won’t use it. And we will be continuing to improve it to meet what developers are asking for.

PhysXInfo.com: Will PhysX SDK support next-generation consoles in the future?

Rev Lebaredian: Here is what we can say: we will always support all platforms that are relevant to our developers, so when the next generation consoles will become a reality, we will be on it.

PhysXInfo.com: Will PhysX SDK remain focused on games/game development area only?

Tony Tamasi: The focus is games. People can use it for visual effects or for manufacturing–that is awesome. And if we can do some incremental work to enable them, we’ll do that when we can, but the focus is games.

PhysXInfo.com: Are you thinking about enhancing PhysX/APEX product line with additional middleware packages, for animation or AI simulation, for example?

Ashu Rege: We work closely with our partners, with Natural Motion, with Autodesk, with game engine guys, but we are not interested in participating in that market; making money selling software. So it is not our goal to enter all of these areas.

PhysXInfo.com: What is the current development course for NVIDIA APEX?

Rev Lebaredian: We have decided to currently focus on two modules that have the highest priority for game developers – Clothing and Destruction.

EvE Online: APEX Clothing will make your hair long and silky

PhysXInfo.com: When we are going to see APEX with PhysX SDK 3 support? What are going to be the benefits, in comparison to current APEX with SDK 2.8?

Rev Lebaredian: Internally we already have version that works with PhysX 3. That’s one of the things on the roadmap. APEX 1.2 is going to be the first version of APEX we’ll release that will support PhysX 3.

Essentially, the benefits will be all the benefits that you get from PhysX 3 – better performance, and we’ll have all new features, new solvers, and all that kind of stuff.

PhysXInfo.com: Are you planning to port APEX to mobile platforms?

Rev Lebaredian: Yes.

Ashu Rege: Internally, we already have all of those working.

Tony Tamasi: And as soon as mobile devices will support CUDA, we’ll have GPU computation on mobile devices too.

PhysXInfo.com: APEX Destruction 1.1 will include fully functional GPU Rigid body solver (you were able to see in Art Gallery demo at GDC 11) – can you provide more details about it? Is this already finished technology or first iteration with many improvements to come?

Rev Lebaredian: We’ve done a lot of work on it since the Art Gallery demo last GDC.  It is more robust now, and behavior is better.  It is essentially the same, or maybe in some cases even better quality than the rigid body behavior in PhysX 2.8

Ashu Rege: We are at the point right now where we have three baseline things working–behavior, robustness and performance. We are continuing to enhance and improve it, especially on the performance front. It is using the exact same API [as CPU RB], except some pieces of the API are not implemented yet, so things like joints are not done.

Art Gallery demo was featuring GPU Rigid Body physics with up to 10 000 individual objects

PhysXInfo.com: What other features are planned for future versions of APEX Destruction?

Rev Lebaredian: There are lots of things we want to do with Destruction, real-time fracturing instead of pre-fracturing, all kinds of stuff. There are a lot of things in the plan and we have ideas on how to implement a lot of them, but what ends up driving features is the content. We work with game developers, see what it is they want, and we will change the priority based on demand.

PhysXInfo.com: New clothing solver was introduced in PhysX SDK 3.1. How does it compare to the previous one?

Tony Tamasi: It is faster and more stable, but it is not complete in terms of the feature set that is in PhysX 2.8, but we are adding those in the future.

PhysXInfo.com: Are you going to expand this new solver with all the missing functionality, or add additional specialized solvers in the future?

Rev Lebaredian: For collision geometry and similar features, we’ll expand the same solver. We haven’t decided yet, if we’ll want to introduce tearing for example.  That is a likely candidate for a different solver, because it never quite solved this problem correctly anyway. Sometimes it is better to have different solvers that solve different problems.

PhysXInfo.com: Will it support multi-core CPUs to the full extent?

Tony Tamasi: Yes

PhysXInfo.com: Are you planning to add this new clothing solver to 2.8 PhysX SDK?

Rev Lebaredian: The plan is if the developers are using PhysX 3.1, they can just use the new solver. If the developers are using 2.8 and they can’t switch to 3.1 for whatever reason, we can take the solver and make it build with APEX, so that they can continue to use PhysX 2.8 for all of their normal physics stuff and also use the 3.1 cloth solver with APEX Clothing.

PhysXInfo.com: Is authoring pipeline going to be different for new solver?

Rev Lebaredian: There are some modifications we’ve made. The parameter space is different and there are some new features, like tapered capsules for collision geometry–we obviously had to change DCC plug-in to support that.

PhysXInfo.com: When are we going to see new clothing solver in action?

Tony Tamasi: In games shipping next year.

As for us, all of the above sounds trustworthy enough and yet promising.

And what do you think ? Tell us in comments.

In a recent interview to PCGamesHardware.de, Ben Wyatt, technical director at Rocksteady Studios, has revealed some technical details about PhysX implementation and GPU PhysX support in upcoming Batman: Arkham City title.

Let’s overview disclosed facts briefly:

• Batman Arkham City won’t use PhysX 3, but PhysX SDK 2.8.4 instead.
• GPU PhysX content will be able to run on CPU, but with significant performance drop (typical GPU exclusive content type, we presume).
• APEX Destruction (destructible objects and walls) and APEX Clothing (clothing simulation on characters, dynamic paper and leaves) modules will be utilized.

Since APEX Particles module was not mentioned, it seems that GPU accelerated particles (smoke, debris) will be based on default PhysXParticleSystem implementation (like in Alice: Madness Returns).

Update: english version of the interview from PCGamesHardware.com

PCGH: Will the PC version of Batman: Arkham City like Batman: Arkham Asylum utilize Nvidia’s PhysX API including support for Physics calculated on the GPU?

Ben Wyatt: Yes. Like Batman: Arkham Asylum, the PC version of Batman: Arkham City will feature realistic smoke, debris, leaves, and paper using GPU PhysX. There will also be features not seen in Batman: Arkham Asylum including clothing on characters.

PCGH: Which of the different APEX modules do you use (Apex Clothing/Particles (Destruction/Turbulence for fluids)? Can you give a short description where in the game APEX will be applied?

Ben Wyatt: APEX destructibles are used in the PC version for breakable elements in the game including breakable walls and objects that get thrown during fights. APEX clothing is used in the PC version for several of the characters you’ll encounter in the game and for simulating effects like paper and leaves. APEX clothing was also used for many of the cutscenes which can be seen on all platforms.

PCGH: What are the visual differences between physics calculated by CPU and GPU (via PhysX/APEX)?

Ben Wyatt: The extra PhysX effects in the PC version of the game add another dimension of realism to the game. When fighting as Batman or Catwoman, you will see walls break into splinters, paper and debris get kicked up, smoke respond realistically, and clothes on the thugs you fight.

PCGH: Are there any features that players without an Nvidia card will miss? What technical features cannot be realized with the CPU as “physics calculator”?

Ben Wyatt: All PhysX and APEX features can be run on the CPU or an NVIDIA GPU, but you can expect the game to run much slower without NVIDIA GPU acceleration when the additional PhysX effects are enabled. An NVIDIA GPU is recommended for all the additional PhysX features.

PCGH: Do you plan to use the latest PhysX SDK 3? Which advantages do you see compared to previous versions?

Ben Wyatt: Batman: Arkham City uses PhysX 2.8.4.

PC version of Batman: Arkham City is supposed to be released in first weeks of November, 2011.

If you are know PhysX only as GPU accelerated physics effects for PC games, lack of news and announcements of new GPU PhysX titles may give you an idea that NVIDIA has decided to drop support for PhysX completely. Forum threads like “Is PhysX Dead?” or “Physx dead?“, popping up from time to time, are indicating – users are worried.

We were able to contact NVIDIA and Mike Skolones, product manager for PhysX, has revealed us the company’s plans regarding PhysX Technology.

PhysXInfo.com: Is PhysX still playing important role for NVIDIA ? Are you planning to use and evolve the PhysX Technology over the years, or thinking about abandoning it in a favor for other solutions ?

Mike Skolones: PhysX has been and continues to play an important role for NVIDIA, as well as for the thousands of game developers who use PhysX for physics simulation across a broad range of platforms, including PC, Xbox360, PLAYSTATION 3, Nintendo Wii , iOS (including iPhone, iPod, and iPad), OSX, Linux, and Android (including NVIDIA Tegra™ devices), MMO servers running Linux and Windows; OSX ports; and Windows games, where GPU-accelerated advanced simulation is poised for continued growth.

Monster Madness - one of the fist games that utilizes PhysX SDK on Android platform

More importantly, because PhysX continues to be the choice of developers for integration into world’s leading commercial game engines, including Unreal Engine 3, Trinigy, Unity, Torque, Gamebryo, Lightspeed, Hero, and Dark Basic, not to mention other internal tech engines which also use PhysX, designers and artists know they have compelling development platforms they can immediately take advantage for making their games that much more realistic and interactive.

PhysXInfo.com: One may said that GPU accelerated PhysX is dead, since there is no new titles with PhysX support on the horizon. Is the situation going to change in near future, and if yes – what are you planning to oppose the inceptive competition (like OpenCL Bullet) ?

Mike Skolones: Actually, there are quite a few titles on the horizon with GPU PhysX support and more developers everyday are enthusiastically exploring this technology with an eye toward making their Windows-based games richer and more exciting. The gaming experience that savvy designers can deliver with GPU-accelerated PhysX remains unparalleled. NVIDIA is making a serious investment in PhysX to solve the simulation problems that are critical to game developers on all of the platforms that are important to their customers. As the mobile computing revolution continues to transform the gaming landscape, this effort provides more and more value each day.

NVIDIA APEX Toolset is supposed to help developers integrate PhysX effects

The PhysX approach is fundamentally different from the open-source alternative, because in practice what really counts is the ability to support the whole spectrum of platforms. Game developers have many conflicting requirements and clearly we want to support them no matter what library they choose to use for design. Of course, the big difference between PhysX and other open source efforts is that NVIDIA is investing in tools and support for PhysX to directly support designers. We help them adopt and integrate our core technologies and we provide regular updates to address their key issues. Today that type of support is not available with open source alternatives.

PhysXInfo.com: After GDC 2011, you have announced first public release of artist-friendly NVIDIA APEX physics simulation framework. Are you planning to update PhysX SDK core (which is still based on old NovodeX engine) to enhance performance/features based on a modern platforms capabilities, and further improve recently added APEX сomponents ?

Mike Skolones: You bet. The PhysX SDK v. 3.0 is now in beta, and is in the hands of a great number of developers. Although PhysX will always have its roots in Novodex, version 3.0 is a solid re-write of the whole core of PhysX. The PhysX-3 code base is now substantially cleaner, which is absolutely critical to achieve optimal performance across all modern gaming platforms.

This week our undivided attention is focused PhysX SDK based multiplayer shooter Breach, notable for its pervasive and complex dynamic destruction system.

Update: PhysX and Breach: Final Verdict

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 cosmetic 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 is 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 $).

With Mafia 2 coming closer to it’s release, hype atmosphere is getting hotter, and apart from other materials you can find on the web, PC Games Hardware has published decent interview with Denby Grace from 2K Czech on several Mafia’s engine features, and PhysX part specifically:

PC Games Hardware: Are there any differences between the Console and the PC Version of Mafia 2 as far as technical as well as visual aspects are concerned, for example GPU accelerated PhysX effects?

Denby Grace: You hit the nail on the head. The biggest difference is the GPU enabled physics effects. While on a system without GPU (consoles and ATI cards), the game will have a great PhysX simulation with particles and cloth, however, if you have the extra hardware we are able to push things to a whole new level which has not yet been seen in open world game before.

Our destructible environments feature thousands of physical particles which in turn can be affected by individual explosion force fields to make them move. It’s all very impressive and it’s these kinds of improvements that high end PC gamers can expect.

PC Games Hardware: We know you are using Nvidia’s PhysX API and also APEX moduls (“Clothing”). Besides PhysX support why did you decide to use Nvidia’s physics middleware instead of other physics libraries like Havok or ODE? What makes Nvidia’s SDK so suitable for your title?

Denby Grace: PhysX is a really scalable system, which is something that appealed to us. We get to integrate a base system that can be dialed up and down, dependant on what system specs the users have. We have a minimum benchmark frame rate that we want to see, then the PhysX simulation level will adjust itself based upon the type of hardware you have.

CPU vs GPU quite simply means that we can really push the boat out with that much dedicated horsepower without being concerned that it’s going to affect the performance of other areas, separating this out is certainly preferable. Going a step further is separating out the gfx from the physics with separate GPU’s (SLI configuration).

People without a GPU PhysX card will still have these effects but it won’t be quite as advanced. We were very careful in ensuring that this would not affect the game play experience, no matter what system you have. , Mafia II I think looks absolutely amazing even without the full PhysX.

PC Games Hardware: Does regular by CPU calculated physics affect visuals only or is it used for gameplay terms like enemies getting hit by shattered bits of blown-away walls and the like?

Denby Grace: No we don’t do this. We didn’t want to alienate a part of our user base with that sort of selective functionality.

Also, don’t forget to check several comparison PhysX screenshots, located at this technical review.

Besides, Gametrailers.com has uploaded an interview with Eric Liu, Nvidia content manager, covering PC version specific features, like 3DVision and GPU PhysX and APEX support.

Decent article called “AMD and NVIDIA butt heads over physics” emerges on Atomic MPC website yesterday.

Richard Huddy, AMD’s Worldwide Developer Relations Manager, Ashu Rege, Nvidia’s Senior Director of Content and Technology, and Nadeem Mohammad, Nvidia’s Director of Product Management and PhysX, are speaking out against physics engines support strategies of their rival companies. During discussion, Bullet physics SDK is opposed to PhysX SDK.

Apart from slight pro-AMD tone and some factial mistakes in engines descriptions, it’s interesting read. Conclusion we are complitely agreed with:

Whether or not Bullet takes off remains to be seen, but the next few years will certainly be an interesting challenge for both companies.

However, as we’ve already took a view at AMD and PhysX relationship history, future of that AMD-promoted GPU Bullet and it’s implementation in games (not Bullet SDK itself) isn’t looking so bright and clear for us.

Recent articles about Metro 2033 have revealed so much technical details (about engine itself, and PhysX components specifically) so, one would think, nothing new can be added. However, recent interview with Chief Technical Officer Oles Shishkovstov by PCGamesHardware.com has something to offer:

PCGH: It could be read that your game offers an advanced physics simulation as well as a support for Nvidia’s PhysX (GPU calculated physics) can you tell us more details here? Does regular by CPU calculated physics affect visuals only or is it used for gameplay terms like enemies getting hit by shattered bits of blown-away walls and the like?

Oles Shishkovstov: Yes, the physics is tightly integrated into game-play. And your example applies as well.

PCGH: Besides PhysX support why did you decide to use Nvidia’s physics middleware instead of other physics libraries like Havok or ODE? What makes Nvidia’s SDK so suitable for your title?

Oles Shishkovstov: We’ve chosen the SDK back when it was Novodex SDK (that’s even before they became AGEIA). It was high performance and feature reach solution. Some of the reasons why we did this – they had a complete and customizable content pipeline back then, and it was important when you are writing a new engine by a relatively small team.

PCGH: What are the visual differences between physics calculated by CPU and GPU (via PhysX, OpenCL or even DX Compute)? Are there any features that players without an Nvidia card will miss? What technical features cannot be realized with the CPU as “physics calculator”?

Oles Shishkovstov: There are no visible differences as they both operate on ordinary IEEE floating point. The GPU only allows more compute heavy stuff to be simulated because they are an order of magnitude faster in data-parallel algorithms.

As for Metro2033 – the game always calculates rigid-body physics on CPU, but cloth physics, soft-body physics, fluid physics and particle physics on whatever the users have (multiple CPU cores or GPU). Users will be able to enable more compute-intensive stuff via in-game option regardless of what hardware they have.

Pay attention to last paragraph – Metro 2033 will feature true multi-core implementation of GPU PhysX content – feature that most PhysX titles are lacking currently ? We are curious to see if this will really work, and since game has already gone gold, we’ll learn that very soon.

Eurogamer.net website has published some very interesting materials, related to upcoming Metro 2033 title.  Firstly, they revealed full specifications of proprietary technology behing Metro 2033, known as 4A Engine, which is called even by its developers “one of the most advanced engines on the planet”.

You can read full specs here, and we’ll quote only part related to engine physics system:

Physics System
Powered by nVidia PhysX technology, can utilise multiple CPU cores, AGEIA PhysX hardware, or nVidia GPU hardware.

* Tightly integrated into the content pipeline and the game itself, including physical materials on all surfaces, physically driven sound, physically driven animations
* Rigid body and multi-jointed constructions. Breakable fences, walls , sheds and other objects. Thousands of different physical entities simulated per frame.
* Cloth simulation, water physics (including cross-interactions)
* Destruction and fracturing, physically based puzzles
* Soft body physics on selected special game entities
* On hardware-accelerated PhysX platforms engine implements full physically correct behaviour of particles such as smoke, debris, etc.

For dessert – Metrospective, interview with 4A Games chief technical officer Oles Shishkovtsov about game engine optimizations and platform specific features.

Metro 2033 is coming out March 16 on PC and Xbox 360, PC version will include 3D Vision, DX 11 and GPU PhysX support.

Update: second part of interview with Oles Shishkovtsov was published on Eurogamer. Provides more in-depth details on PhysX SDK integration, and engine’s genesis in general.

Digital Foundry: The 4A engine integrates NVIDIA PhysX. What are the core advantages of the hardware acceleration, what sort of hardware do you require for the best experience?

Oles Shishkovstov: The core advantage is simply the performance. The CPUs just aren’t there to enable large-scale physical effects (although they are very competitive when processing traditional rigid-body things). However, when you offload costly PhysX processing to GPU, we’ve got less GPU time for rendering.

It’s a difficult question when choosing what hardware will provide the best experience. I’d say that dedicating another (maybe less powerful) GPU specifically for PhysX is the right thing to do!

Digital Foundry: Over and above the tech demo-style elements that make PhysX cool, can you explain to us how the physics add to the gameplay experience?

Oles Shishkovstov: We do not add PhysX effects if they aren’t integral to the gameplay experience. We don’t add an effect for the sake of an effect. Human eyes and brain are trained to see the inconsistencies. We are only trying to remove those inconsistencies in order to not distract from gameplay and not to lose that immersion we were heavily building brick by brick.

Digital Foundry: How did you integrate PhysX into your many-core engine assuming you don’t have hardware acceleration? Are the same principles in use in the Xbox 360 code?

Oles Shishkovstov: That’s easy. PhysX SDK has the similar notion of the “task” as we use. The SDK spawns them for every operation which can be safely parallelised, for example each rigid-body shape-shape collision detection, each cloth or fluid update, even the solver(s) is heavily sub-divided into the tasks.

We forward those tasks to our task-scheduler and they are processed in the same manner as everything else. The only “conceptual” difference is between their and our task-model – we “spawn-and-forget” tasks and PhysX uses a “spawn-and-wait” model.

Gametrailers.com website has published exclusive video interview with Luis Gigliotti, Metro 2033 executive producer, which also includes new gameplay sequences.

First part give a glimpse on human survival in Moscow after nuclear strikes.

In second part Luis describes new proprietary engine used to produce highly detailed post-apocalyptic world plus new innovative weapons.

In addition to excellent graphics with DX11 support and intensive storyline, Metro 2033 will include GPU accelerated PhysX content. If you are interested in details about GPU PhysX support, please refer to our  inteview with 4A Games, focused on in-game physics.