Sundog Blog

Posted by Frank Kane on 9th April 2015

Announcing SilverLining 4.

SilverLining Software Development Kit for Windows

SilverLining 4's new stratus clouds featured in X-Plane's SkyMaxx Pro 3 add-on.We are stoked to announce the release of SilverLining 4.0!

SilverLining 3 brought you much-improved cumulus clouds, and in SilverLining 4 we’ve turned our attention to vastly improving our stratus cloud layers. No longer are stratus clouds just flat planes with fog sandwiched in between them – they are now fully 3D, featuring a simulation of atmospheric scattering never before seen in real-time. Check out these features of our new stratiform clouds:

  • Simulation of first-order, second-order, and multiple scattering
  • Real simulation of Mie scattering down to 0.1 degree resolution
  • Fogbows, glories, and anti-solar points that just fall out of the math naturally
  • Scattered or solid stratus cloud layers with adjustable scud range
  • Ambient occlusion on cloud tops
  • Silver linings on backlit clouds
  • Fast performance
  • Curved-Earth and geocentric/ECEF coordinate system support
  • Infinite and localized areas of clouds
  • Variable cloud coverage

Fogbow on stratus cloud in SilverLining 4One of my favorite things is how optical effects like fogbows just happen naturally as a result of the math, as seen in this screenshot. Every part of these clouds are driven by a real physical simulation, from the convective noise that forms the basis of the cloud shapes, to every nuance of their lighting. A thin, 400 meter thick stratus cloud will look very different from a 1000 meter stratus cloud for example – just as it would in real life. (The thinner one will look more visually interesting, by the way – 400 meters is actually a good choice for best results.)

Broken stratiform cloud in SilverLining 4.0You can also create stratiform clouds that aren’t solid, as seen here. This can create a lot more depth and visual interest to the cloud, although we recommend using high coverage values like 80-90% with stratus clouds. While you can go lower, you’ll get a better representation of lower cloud coverage with SilverLining’s existing cumulus congestus clouds – especially the high-resolution version of them.

Even though this is a major version bump, SilverLining 4’s API is unchanged. So, updating is a cinch. Your stratus clouds will just start looking a lot better. They’re still fast too – we get hundreds of frames per second, even when drawing a 200km-wide stratus cloud layer.

We’re very excited by the visual quality and performance of these new clouds in SilverLining 4.0. As always, we’ll continue to iterate on them given your feedback as well. SilverLining 4 is available now from our SDK evaluation page, and licensed users have access to its source code as well.

SilverLining Software Development Kit for Windows

Posted by Frank Kane on 31st March 2015

Triton 3D Water Updated for Unity 5

Triton Oceans for Unity 5A new update of our Triton 3D Water for Unity product is now available, including updates to support the new Unity 5 release and the latest Oculus Rift SDK. Get the latest no-risk trial version to evaluate, or you can get the update through the Unity Asset Store.

If you’re developing with the Oculus Rift, this update is a must – not only does it work with the latest 0.4.4 version of the Oculus SDK, there are some important bug fixes with the Oculus Rift integration you’ll want for sure.

Unity 5 now offers native plug-in support as part of its free version, so that means Triton no longer requires the Pro version of Unity! Any Unity user targeting Windows or MacOS can now use Triton to add the most realistic 3D oceans available to their project. Our update also continues to work with Unity 4 Pro, so if you’re not ready to update to Unity 5 yet, that’s OK.

If you’re evaluating Triton for the first time, be sure to read the documentation as it is a complex asset, and sometimes it needs to be adjusted to account for post-processing effects and transparency in your scene.

Not using Unity? Have a look at our C++ SDK instead, which integrates with just about everything else.

Posted by Frank Kane on 26th March 2015

BlueSkies: Pro-Level Skies and Clouds for Unity

BlueSkies for UnityOur friends at AgileSrc LLC have released BlueSkies – a new version of our SilverLining Sky, 3D Cloud, and Weather SDK built for the Unity engine. This brings the same dynamic, procedural sky and 3D cloud effects used by our pro C++ developers to Unity for the first time.

While we’ve offered a stripped-down, inexpensive version of SilverLining for Unity in the asset store for some time now, BlueSkies is a native wrapper around the complete C++ version of the SilverLining SDK. That means you get access to all of SilverLining’s professional-grade features used by simulation and game developers around the world, including precipitation effects, a wider variety of cloud types, a more sophisticated procedural sky, multiple cloud layers, and highly optimized native code for the best performance.

BlueSkies is sold and supported exclusively by AgileSrc LLC; contact or visit the BlueSkies website for more information.

Posted by Frank Kane on 12th March 2015

Tuning Precipitation Effects in SilverLining

Beaufort scale 9 in TritonThe #1 most-asked tech support question we receive is:

“When I enable rain or snow in SilverLining, my clouds disappear!”

This falls into the categorgy of “it’s not a bug, it’s a feature.” SilverLining simulates reduced visibility in the presence of precipitation, and since the clouds are usually very far from the camera, they are often entirely obscured when you’re in the middle of heavy precipitation. We handle visibility effects on clouds by fading them out with distance, in order to ensure they blend smoothly against what may be a non-homogeneous sky behind them.

We determine the proper visibility as a function of snowfall precipitation rate using equations in the following paper:

Rasmussen, Vivekanandan, Cole, Meyers, Masters, “The Estimation of Snowfall Rate Using Visibility”, 1999, Journal of Applied Meteorology, Vol. 38, pp 1542-1563

For rain, our reference is:

Atlas, David, 1953, “Optical Extinction by Rainfall”, Journal of Meterology Vol. 10 pp 486-488.

However, many customers find our reduction in visibility to be too aggressive. There are ways to adjust it to your liking.

First, look for these settings inside the Resources/SilverLining.config file included with the SilverLining SDK:

rain-visibility-multiplier = 1.0
snow-visibility-multiplier = 3.0
sleet-visibility-multiplier = 1.0

Increasing these settings will increase the visibility for a given precipitation rate. You may also disable the effect entirely by setting:

enable-precipitation-visibility-effects = no
apply-fog-from-cloud-precipitation = no

If you do this, we do recommend that you manage your own visibility reduction in the presence of precipitation instead. Heavy rain or snow against a clear, sunny sky not only looks unnatural, it makes the precipitation particles hard to see against the bright background. Precipitation will look best with overcast conditions, when you have a stratus cloud layer in the scene with 100% coverage.

While you’re looking at SilverLining.config’s precipitation section, you’ll see there are many other settings that allow you to adjust the brightness, width, and number of particles. If you want rain particles to be more easily visible, or for precipitation to appear heavier overall, these settings will allow you to do that.

Another common question we get related to precipitation is:

Rain or snow looks fine on the front channel of my simulator, but doesn’t look right on the side channels.

SilverLining by default will try to reverse-engineer your projection matrix, in order to pull in the near clip plane to ensure precipitation particles near the camera are visible, and also to enforce a minimum particle size that will project to some minimum size in pixels. However, some exotic projection matrices on multi-channel displays can mess up our math. In this case, be sure to set your near clip plane to something close to the camera, say no more than 1 meter, and disable these effects by setting:

rain-minimum-pixels = 0
sleet-minimum-pixels = 0
snow-minimum-pixels = 0

rain-use-depth-buffer = yes
snow-use-depth-buffer = yes
sleet-use-depth-buffer = yes

That should clear it up.

SilverLining takes great care to provide physically-realistic precipitation effects, but if you need to tune them, we provide lots of ways to do so. If you need further guidance, don’t hesitate to contact

Posted by Frank Kane on 11th March 2015

Triton Ocean SDK Performance Tips

Rough Seas with Triton at duskLooking to squeeze a few more frames per second out of the Triton Ocean SDK? Here are a few tips on maximizing performance when using Triton.
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Posted by Frank Kane on 2nd March 2015

About SilverLining Skies & 3D Clouds for Unity

SilverLining and Triton for UnityIt’s not something we promote much, but we do offer a special version of our SilverLining product for the Unity engine in the Unity Asset Store. Often, Unity customers will come here to learn more about it, but confuse the Unity version with our flagship C++ SDK instead.

They’re not the same thing, and the different price points ($100 vs $2500) should tip you off on that. SilverLining for Unity is something we built for the larger, low-budget indie game development crowd, and to keep its price low, we had to restrict its feature set. SilverLining for Unity is written from the ground up in C# within Unity’s framework, so although it shares some algorithms with the C++ SDK version, that’s about it.

SilverLining for Unity includes dynamic, procedural skies (including stars) for any time of day or location using the Preetham sky model, and 3D billboard-based cumulus congestus clouds for any given coverage. Stratus and cirrus clouds are also offered as part of the package. Because it was written from scratch for Unity, it is compatible with any platform Unity supports, including mobile platforms such as Android and iOS. It also provides direct and ambient light sources for your scene, so your lighting will match the time of day you are trying to simulate, automatically. This is a big part of the much-touted “global illumination” promised by Unity 5, but SilverLining’s been offering this piece of it for years.

What SilverLining for Unity doesn’t include are things like precipitation effects, GPU ray-casted stratocumulus clouds, support for geocentric, round-Earth terrains, cumulonimbus clouds and thunderstorms, crepuscular rays, Hosek-Wilkie skies, high-resolution cloud textures, sandstorms, or support for any platform other than Unity. And at $100, the technical support we can provide for Unity is of course limited.

However, many of those features, such as precipitation or crepuscular rays, are available from other inexpensive assets for Unity that complement SilverLining well. A larger offering for Unity at a higher price may come in the future, but for now please keep in mind that SilverLining for Unity and SilverLining for C++ are two different products with very different prices and feature sets.

Hopefully this will help clear up some confusion from our Unity customers.

Posted by Frank Kane on 11th February 2015

SilverLining Performance Tips

SilverLining clouds and crepuscular rays in the X-Plane SkyMaxx Pro add-on.Looking to maximize your FPS when using the SilverLining Sky, 3D Cloud, and Weather SDK? We’ve made SilverLining highly configurable, so you can choose your own tradeoffs between visual quality and performance. Here are some tips for turbocharging SilverLining in situations where performance is critical.
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Posted by Frank Kane on 10th February 2015

We’re training astronauts.

Well, in our own little way. Sundog Software is involved with Project PoSSUM – a program to study noctilucent clouds from manned, suborbital flight next year. It presents an alternative to space tourism where you can conduct real science, and not just go along for the ride.

Training for Project PoSSUM, literally under pressure.

The first batch of 9 future astronauts were at Embry-Riddle Aeronautical University yesterday for simulator training, while wearing their pressurized flight suits. Sundog Software developed the simulator’s visual simulation of noctilucent clouds, which allows the students to practice identifying the clouds from the ground, flying through them, and imaging them using the “PoSSUMcam.” Little is currently known about noctilucent clouds, but the principal investigator worked with us to develop a model of how these clouds are illuminated, where they form, and how light scatters within them. Their simulator was built using X-Plane, which we’ve worked with before.

Noctilucent cloud simulation for Project PoSSUM

I had the chance to sit on a few of the simulated training flights – hanging out with astronauts training for flight is not something you get to do every day! Also on hand was a camera crew producing a documentary on this project, which I’m looking forward to seeing later on.

Project PoSSUM sponsor banner

Overall the training went smoothly – feedback on our simulated clouds was good all around, and the team learned a lot from the experience. We at Sundog wish continued success to this truly unique program.

Posted by Frank Kane on 4th February 2015

Check Out our Latest Demo Reel.

YouTube user redpiper1 has updated our demo reel with new footage from our SilverLining Sky, 3D Cloud, and Weather SDK, Triton Ocean SDK, and the SkyMaxx Pro add-on for X-Plane that features SilverLining. As usual, he’s knocked it out of the park:

Be sure to watch it in full-screen, HD glory!

Posted by Frank Kane on 25th January 2015

New X-Plane Video featuring SilverLining’s Clouds

YouTube user “redpiper1” has released another amazing fan video of the X-Plane flight simulator. It includes a lot of great shots of the SkyMaxx Pro add-on for X-Plane which is built using our SilverLining Sky, 3D Cloud, and Weather SDK. But even though that’s not its focus, it’s just a great flight simulation video that we wanted to share.

Go ahead and watch it fullscreen in all of its HD glory!