New to Beyond Casual? – start from part 1!

Part 6 : Flying

Joust (1982)
One of the oldest cross cultural dreams involves flying. Humans always looked up with envy at birds, as they fly across the sky. We learned to build machines that help us compensate for our lack of wings or sufficient strength, but boxing ourselves also means we lost the craved free flight experience. And when we try to get it back, it is extremely dangerous – physics punish us with the great gravitational pull of earth. Goodbye Newton – I am switching to my virtual world!

Lilienthal’s “Fliegeberg (1894)


Let’s first discuss unpowered flight first.

A natural full body gliding control can be inspired from free-fall skydive sport

Gliding forward by holding the hands backward
Putting the hands closer to the body reduces the lift and increase speed of fall (This can be related to the angle of the hands)
Moving the hands down, reduces drag speed, and increase forward motions, while spreading the arms slows down the gliding

Regardless of the hand poses, actual body rotation should also control bearing/pitch/yaw in parallel 

Flapping wings (Ornithopter)

Moving the hands down creates lift. In our simplified model – we can ignore the up motions (Unlike birds – it would be OK if don’t really have to fold our ‘wings’ in the process)
This lift gets stronger with the down motion

Once airborne – the lift gets x3 stronger (So the best way to liftoff, is to first jump together with a strong flapping motion)

The same mechanics can also support special super-jumps: if the user simply jumps and uses his hands too – he will reach higher altitudes!

Building a physical model 

A full physical model is of course an overkill – but a carefully thought simplified model can encapsulate the diversity of behaviors we require. Going back to high-school physics books to refresh our knowledge of moments, torque, and trigonometry can get us to a sufficient point (And to think you thought it will never be useful…). 
We assume two rectangular ‘wings’, without any airfoil
  • Lift forces are generated by the air-drag below the wings, and in the upwards normal direction. The force magnitude is a factor of: the combined virtual speed and the local hand motion, as well as the angle between the wing and the air flow vector
  • Moving the hand s up changes the wing angle accordingly
  • Moving the hands forward/backward may also change the wing rotation

You can freely add constants such as wing surface, drag factor, and the universal gravity constant (g) – all those should be tuned until you reach a fun experience, that matches the dynamics of the game.

And ppppplease: you don’t need HW accelerated Physics engine to simulate a couple of trigonometric function per frame…


The Flying Moonman / ahillel 
Why bother flying with wings when we can have jets?
Control model can simply use the hands as two elements that can add drag
This will translate to the following gestures:

  • ·         Slow down when spread around
  • ·         Control pitch when moving hand together forward and backwards
  • ·         Roll with one hand forward and another backwards
  • ·         Change yaw/bearing by spreading only one hand

 "jetman" Yves Rossy

Chicken and egg problem?

OK – so we can fly. It still does not mean it’s going to be fun. If you play with any of the available bird/dragon controlling games, you will discover most don’t really give you the satisfaction of flying. If it’s too easy to fly – it just feels like another flight simulator.  If it’s too hard to fly – we are back at fitness vs. fun equation of the previous post. We need to find some special game dynamics that will actually make it fun and challenging.
Daedalus and Icarus

  • You can upgrade to allow flying by collecting/applying limited magic. Imagine a game where you eat a special potion that turns your hands into wings à so your flapping lift gets amplified…
  • For the Darwinists, you can evolve and gradually increase your wing surface (So you begin as a chicken and end as easily gliding eagle – of course this has nothing to do with natural selection)
  • Alternately, you can create a game logic where everything is possible without flying – by walking. You break the fitness/fun equation by only allowing the user to fly a bit in order to jump higher / faster. The level design should not encourage your players to overuse it.


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