How It Works: Air Pillow

 

 

The new improved near-ground flight system, also known as the "Air Pillow", was introduced in update 1.9.5. It is a complex feature that combines a modified control system, in-game physics, and damage model tweaks, as well as new visual effects. Our goal was to make low altitude flight more impressive and less dangerous. Now you don’t need Jedi reflexes to enjoy hedge-hopping in your warplane. Nevertheless crashing into terrain is still a real threat and a common in-game situation if you are not careful, after all World of Warplanes is still the game where you pilot combat aircraft.

Modified physics

Prior to 1.9.5 we had a mechanic that pushed aircraft away from terrain at low altitude. It mostly did what it was supposed to, but still had some drawbacks. It worked poorly over inclinations, didn’t take complicated landscapes into consideration, and didn’t work at all over static objects. In the new system the vector of force applied to the aircraft is calculated from the normal to the terrain and thus is effective over both water and mountain slopes.

Additionally it is able to consider possible collision points and push the aircraft away not only vertically, but also laterally. This is most effective when the aircraft is positioned with its wings parallel to the terrain. If the terrain is inclined the system increases the speed of movement directed away from the collision point.

This system makes low altitude flying over complicated terrain easier and helps when exiting steep dives. It was created to decrease the chances of occasional collisions and crashes. Nevertheless, if the player deliberately points the aircraft downwards, the system won’t stop them from crashing into terrain.

Modified control system

Lower mouse sensitivity at low altitude

While the aircraft is flying close to the ground, the control system applies a lowering coefficient when calculating responses to a cursor aimed towards terrain. It can feel like an elastic pillow that pushes the cursor back from the ground, but in reality it has nothing to do with in-game physics. It is a control system tweak that smooths occasional cursor movements when flying low.

Raising the nose in sharp maneuvers

If “Limit bank angles at low altitude” was enabled in the Advanced controls settings, a sharp turn (when the cursor is moved far from the center of the screen horizontally) on an aircraft at very low altitudes would be very slow because it would mostly use just the yaw axis. The system would prevent it from using roll and pitch to turn effectively in order to limit the chances of a wing hitting terrain.

Now once the control system receives a “sharp turn” input at low altitude it will raise the nose and execute the turn much faster using pitch.

Automatic pitch correction at low altitude

When maneuvering close to the ground, the aircraft always aims to align itself parallel to the terrain. Sometimes this helps to avoid small obstacles. Once the aircraft aligns its flight vector with the cursor pointer the automatic correction is disabled.

Visual effects when flying close to terrain

We added two effects that are applied when you fly close to terrain, the camera is blown over with particles and a particle trail appears behind the aircraft. These particles depend on the terrain type — water, ground, sand or snow. Besides being visually engaging, they serve as a warning that you are dangerously low.

Other changes

We also made several changes that are not directly linked to physics or controls but still make low altitude flying more comfortable.

Modified collisions with terrain

Update 1.5.0 added changes to the collision system. Collisions were split into three categories, hard, soft and semi-hard. The aircraft started taking less damage from ramming into each other, occasional friendly collisions became less deadly. Update 1.9.5 took a step further along those lines. We aimed to lower the chances of occasional aircraft destruction.

From now on, collisions with terrain can also be hard or soft. Occasional grazing with a wing or undercarriage now deals a small amount of non-lethal damage. Hitting terrain with the fuselage will still immediately destroy your aircraft.

Modified damage from trees

Prior to 1.9.5, hitting a tree always dealt 10 HP damage per server tick. This lead to situations when lower tier aircraft could suffer a lot of damage from hitting just a couple of trees and be forced to spend the rest of the battle conserving their remaining HP and trying to survive. Conversely, having 200-300 HP meant that you could mostly ignore foliage and batter through it on approach to ground targets.

Now hitting a tree deals damage proportional to the maximum HP count of the aircraft and thus is equally dangerous for all tiers, forcing players to be more cautious and precise when piloting.

Damage from trees varies depending on classes. Attack aircraft have a rugged and armored airframe, thus they take the least damage from collisions.

Summary

Overall we have reached the goals that we aimed for when developing this system. Flying low became more dynamic, spectacular and entertaining. You can now literally hedge-hop and feel the speed and power of your warplane. This is especially impressive due to the new visual effects.

The number of aircraft crashing into terrain has decreased over all classes. At the same time, the proportion of these occurrences remained the same when comparing classes against each other.

You can still crash your warplane if you are too reckless or force an enemy to crash when maneuvering dangerously low. But these maneuvers need to be extremely precise, when the difference between evading the ground and hitting it is determined by a couple of meters, which can only be achieved by skilled pilots.

The "Air Pillow" system is deeply integrated into the game engine both on the client's and on the server side, it cannot be disabled because we aim at providing all players equal conditions for maneuvering and fighting.

We have further plans to improve the current system:

  • It will be slightly tuned to decrease the “floater effect” close to the ground. It will become easier to push the aircraft ever closer to the terrain, making strafing runs at minimum altitude easier.
  • Improvements to visual effects will make particles more impressive, the effects will gradually increase and decrease their intensity depending on the distance to the terrain. We plan to add an effect for grazing the wing on terrain that will show exactly where it collided, so feeling your aircraft’s dimensions will be easier. We will also add another effect for collisions with trees — leaves will start flying over the canopy.

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