"One of our upcoming innovations for trueSKY 4.2 is geographic weather – you can have entirely different weather states in different parts of your game world – a storm rolling in from the East with clear skies in the West for example."

We interviewed you back in late 2013. It is now more than 4 years. Can you let us know what has changed at Simul in this period?

We’ve grown! We have tripled our full-time staff, and moved to larger offices here in Liverpool. Most of our business now is for engine plugins, though the standalone trueSKY SDK is still very important. But the whole industry has moved towards standard commercial engines: Unreal, Unity etc. We’ve really opened up to indie developers as well, and have started to build a great community of trueSKY enthusiasts.There’s a convergence happening where indies and triple-A’s are starting to use a lot of the same tools and techniques, and we’re excited to be a part of that process.

How has your flagship product TrueSky evolved in the last four years?

VR support changed a lot for us: you simply can’t leave any performance on the table if you want to be in VR, so that’s driven us to really stamp down on clock cycles. At the same time, we must keep evolving the feature set. In 2013, we were almost the only people doing volumetric clouds in real time. Now it’s become commonplace – many triple-A studios have had a crack at it – so we have to be the best. We used to have two types of cloud: 3D volumetric clouds for cumulus and so on, flat 2D clouds for high-altitude wispy cirrus clouds. In trueSKY 4.2 those are all done volumetrically, nothing is flat. I think our 3D cirrus clouds are the first of their kind in real time. You can have as many cloud layers as you like, all blending together, evolving over time.

Can you tell us how Simul Weather has evolved in this period?

One of our upcoming innovations for trueSKY 4.2 is geographic weather – you can have entirely different weather states in different parts of your game world – a storm rolling in from the East with clear skies in the West for example. Then the storm reaches you, the whole lighting changes.

But while we have good ideas of where we want the product to go, we try to give the customer what they want. Several studios told us they love trueSKY’s visual quality, but have no need for dynamic skies. So we’ve implemented a feature where trueSKY will generate a skybox when requested, update your lighting, then stop: the CPU and GPU cost of that per-frame is essentially zero.

Can you give us some examples, if possible, of games that have used these two technologies and the challenges you have faced?

When Bandai Namco first came to us with a request for skies in Ace Combat 7, they explained that they would want to make an emphasis on VR. We found that we had to completely change the way we draw volumetric clouds in order to look good with a headset.Because we render our clouds at a lower resolution than the screen, slight motions of the VR headset could cause aliasing artifacts. So we invented a world-space volumetric renderer that produces a stable image that looks good from any angle. The quality of what BN have achieved with it is astonishing.

"We always try to use as little as possible. It’s become almost as important as GPU time for us because every bit of memory we use is denying that space to some other part of the game."

Back when we interviewed you, the world was getting ready for next-gen consoles i.e. the PS4 and Xbox One. Now we have two new iterative consoles i.e. PS4 Pro and Xbox One X. How have you upgraded your tools for the same?

The main difference for us has been the move to 4k, and to HDR. Fortunately, trueSKY was already outputting physically accurate linear radiance values, so the information was already there waiting for an HDR display to output it. It’s been quite transparent for us.

Did you incur any additional development expenses for supporting the new iterative consoles?

Yes – not only buying the devkits, but also the expense of 4K HDR screens. And at GDC this year we’ll have at least one of those, so it makes that a more expensive process.

In our last interview we discussed about how the new consoles have 8GB of memory. Now we have an interesting position with the PS4 Pro and Xbox One X. The former has 8GB and the latter has 12GB. How do you this impacts Simul or for that matter games development in general?

We always try to use as little as possible. It’s become almost as important as GPU time for us because every bit of memory we use is denying that space to some other part of the game. We aim in a typical scenario on console to use less than 30 Mb. But that will rise to about 50 if you want very high-res clouds, as might be the case on PS4 Pro or Xbox One X.

Simul Software is GPU based tech. This raises an interesting question. The PS4 Pro has 4.2 TFLOPS GPU whereas the Xbox One X has 6. Does this mean you are able to extract more out of the X and in what ways?

Yes, it allows more work to be done in the same GPU time, so if a developer allocates 1.5ms for the sky, trueSKY can do (on Xbox One X) almost four times more work: rendering the clouds at double the resolution for example. If you want to use the extra power to go from 30fps to 60, you can still do about twice as much per frame, so resolution could go up by about 30%.

Simul Software is the face of new technology. You guys develop tech which will be used for the next 5-10 years. How do you see a potential PS5 and next Xbox changing the gaming landmark?

I anticipate a big move towards procedural content in the next generation or two. The generation of content is not limited by computing power, space or even bandwidth so much as the human capital that’s expended in creating it. I think what we’ve pioneered with skies in terms of 100% generated content, albeit with artistic input and programmed control, will become the norm for 3D objects, textures and gameplay elements. None of that takes away from the craft and creativity that goes into games, it’s a new set of tools that developers will use in ways we can’t yet imagine.

"We’re working on Switch right now, and expect to launch trueSKY for Switch within the next few weeks!"

I find it surprising that Simul is not on Nintendo Switch, specially given the hybrid system’s success. Is there a specific reason for this or is it due to its low processing power?

We’re working on Switch right now, and expect to launch trueSKY for Switch within the next few weeks!

GDC 2018 is coming up. Can you share your plans and what exciting new tech will you possibly be showing off?

At GDC 2018 (booth 1914!) we’ll have playable games featuring trueSKY running the gamut from super-cool indie projects to triple-A blockbusters. We’ll be showing trueSKY 4.2, which is a quantum leap in visual quality and power over what we’ve had before. And we have a beautiful new water system, based on the same principles as trueSKY: seamless integration, physically-based parameters, and high performance.

Is there anything else you want to tell us before we let you go?

We’ve been completely blown away by the quality of some of the indie games in the trueSKY community, and we’re super-excited to see what they come up with next.

"The atmosphere is a double threat for games developers. It’s a complex system, and the end user is intimately familiar with what it really ought to look like."

Ravi Sinha: Tell us about Simul and the first games that utilized it. What was the goal back then for the software and how have priorities evolved over time?

Roderick Kennedy: We originally wrote CloudWright, a tool to generate static skyboxes for games. While it produced some good results, it seemed that the technology we’d developed would actually work in realtime with good framerates, so we decided to make the jump, creating Simul Weather (later called trueSKY). Our first customers were in the simulation field – companies like Boeing and CueSim. Later on we had great games companies like Bohemia Interactive with the ARMA series, Gaijin with their awesome flight sims, and Ubisoft.

Ravi Sinha: Given the next generation of gaming, which is nearly upon us with the PS4 and Xbox One, where does Simul come in with its ability to accurately model weather?

Roderick Kennedy: The atmosphere is a double threat for games developers. It’s a complex system, and the end user is intimately familiar with what it really ought to look like. If you’re shooting for visual realism, hyper-realism, or detail – as opposed to abstract or cartoon-style graphics – the days of static skies or rotating skyboxes are past. Developers want to show that they are fully on board with the next generation, and we can do that for them – at least where the sky is concerned.

Ravi Sinha: We’ve heard about how both consoles are powerful to handle dynamic worlds, detailed animation and the latest engines. But of the two consoles, the PlayStation 4 and the Xbox One, which one is more equipped to handle realistic weather effects?

Roderick Kennedy: There’s little difference really. TrueSky works very well for both, and most of the underlying code is the same. The real difference is between this generation and the last, and that’s reflected in the level of demand we’re seeing for trueSKY now.

"The challenge for developers is always to fit everything in – leaving enough power for solid rendering, effects, post-processing and environment rendering. It’s our job to make ours as lightweight as possible, so we’re always looking for new optimizations."

Ravi Sinha: Along with many other features, Simul supports DirectX 11. With more games looking to be geared towards DirectX 11 (and 11.1) in the coming years, how will they be able to take advantage of Simul in comparison to games in this generation?

Roderick Kennedy: One area with huge potential is volumetric rendering. In the DX9 era we were able to effectively simulate raytracing for volumetric clouds, and got great results. But the shaders were too limited to do some of the more advanced volumetric effects we wanted. Now those restrictions are removed, we’re able to really go to down – our new crepuscular rays was not feasible on DX9, but on DX11 it’s not only possible, but super-fast.

Ravi Sinha: Given the abundance of RAM with next generation consoles, how will the super-low memory footprint of Simul come into play?

Roderick Kennedy: The challenge is more about bandwidth than RAM. Because we do most of the work on the GPU, trueSKY initializes very quickly. I’d like to see games do much more procedurally, and take loading times back down to how they were in the cartridge era. We’re doing our bit!

Ravi Sinha: With the PS4 and Xbox One, is it possible to let the hardware handle every single environmental effect without any fear of running low on memory?

Roderick Kennedy: Yes. At least, every one of ours. The challenge for developers is always to fit everything in – leaving enough power for solid rendering, effects, post-processing and environment rendering. It’s our job to make ours as lightweight as possible, so we’re always looking for new optimizations.

"We were computing clouds before cloud computing was cool! But for big online worlds we envisage a situation where continental-scale weather systems are computed in the cloud and shared across all the players in a zone…"

Ravi Sinha: We’ve heard Infinity Ward talking about how they would only add such features like environmental effects, including realistic fog that the player can walk through, if their games require it (case in point, Call of Duty: Ghosts). But from your perspective, how will the next generation of gaming benefit from more realistic weather effects?

Roderick Kennedy: It’s interactive. We provide clouds you can fly through, walk or drive through. On holiday last year I was driving up a mountain through 5-metre fog, it was pretty spooky, and we weren’t sure that we’d reach the top or have to turn back. Then we came out of the top of the clouds and it was a beautiful sunny day, with clouds below us in the valleys. With trueSKY we can reproduce that kind of experience in-game. There are many opportunities for a realistic environment to change your game experience.

Ravi Sinha: Sky Sequencer promises a “production-quality toolset”. We’re going to assume film production here, but as the next generation rounds the corner, how much more possible is it now than before for Simul to be used to create weather effects that rival major motion pictures?

Roderick Kennedy: I’ve seen some dodgy-looking clouds in big-budget movies, presumably because the tools are not yet available in offline rendering software to make realistic ones – or at least it’s very much dependent on the artist’s skill. We provide a very specific toolset based on the science of light scattering and the atmosphere. And we’re looking into what’s needed for offline rendering, but real-time is our main preoccupation.

Ravi Sinha: The PS4 and Xbox One emphasize Cloud computing as much as games and hardware. Can Simul take advantage of the Cloud in order to better games? Is it possible for different combinations of effects to be handled by the Cloud while the console hardware is freed up for other tasks?

Roderick Kennedy: We were computing clouds before cloud computing was cool! But for big online worlds we envisage a situation where continental-scale weather systems are computed in the cloud and shared across all the players in a zone…

"We’ve been waiting seven years for consoles to take a step forward, and now we’re full-speed ahead. For us, the new generation is a playground!"

Ravi Sinha: Can you please talk a bit about trueSky and how it is being used to create realistic skies on next gen consoles?

Roderick Kennedy: Our customers work in tandem – artists and level designers use the Sky Sequencer to create effects, while the programmers work on integration. Now that our next-gen libraries are mature, the latter process is quite straightforward. But AAA developers are always ambitious – looking for new effects and new ways to exploit our system for gameplay. So we provide a lot of support, either remotely or on-site.

Ravi Sinha: Is there still a massive gap between the capabilities of next gen consoles in creating realistic weather compared to high end PCs  or is the gap between them and PCs even smaller than with the previous generation?

Roderick Kennedy: The gap is small now. But PC’s will inch ahead incrementally, while the consoles are fixed for a generation. And there’s a lot of exciting things happening on other platforms too, such as mobile.

Ravi Sinha: Are you guys working on any improvements to Simul? Any new features planned for the technology?

Roderick Kennedy: We’ve got a shocking new lightning effect coming soon. We also have some really exciting next-gen features that we’ll be launching next March… We’ll be previewing these on our website at www.simul.co.

Ravi Sinha: Technology is improving at a rapid pace and as such do you see a saturation point for this technology (Simul) anytime soon?

Roderick Kennedy: No! We’ve been waiting seven years for consoles to take a step forward, and now we’re full-speed ahead. For us, the new generation is a playground!

Kennedy stated, “There’s little difference really. TrueSky works very well for both, and most of the underlying code is the same. The real difference is between this generation and the last, and that’s reflected in the level of demand we’re seeing for TrueSky now.”

With more games taking advantage of DirectX 11/11.1 in the coming years, how will they be able to take advantage of Simul’s programs in comparison to current-gen games? Kennedy responded that, “One area with huge potential is volumetric rendering. In the DX9 era we were able to effectively simulate raytracing for volumetric clouds, and got great results. But the shaders were too limited to do some of the more advanced volumetric effects we wanted.

“Now those restrictions are removed, we’re able to really go to down – our new crepuscular rays was not feasible on DX9, but on DX11 it’s not only possible, but super-fast.”

Stay tuned for our full interview with Roderick Kennedy next week.