APD Week 5 - Forces

Theme

I studied physics in high school and have loved it ever since so this topic is really one of the more interesting ones for me. “A simulation is a procedural representation of aspects of ‘reality.’”, Rules of Play, p404 (2004)

Physics engines in games present a range of very interesting problems when it comes to representing the forces which shape our universe and those challenges often come down to the accuracy of the simulation vs the resources available.

“Making a simulation is a process of abstracting—of selecting which entities and which properties from a complex real phenomena to use in the simulation program.”,  Rules of Play, p417 (2004)

There is however a more conceptual layer to resolve when designing the representation of forces in a game.

“Meaningful play stems from the ability of players to make meaningful choices from a limited set of knowable options. If a player has trouble recognizing everything that is being simulated, an understanding of knowable options decreases.”, Rules of Play, p417 (2004)

Latham (2016) discusses the need to maintain the lowest resource demand in the design of any physics system in a game world. With this in mind I wanted to explore the requirements of a wind simulation for use in a 3D environmental puzzle design.

Key Questions:

• How can I represent the influence of naturally changing wind in a 3D environmental puzzle game?
• What kind of game elements might incorporate wind as a force into their design?
• How can I represent natural changes in wind direction and velocity in a simple way?

Context

For many of my experiments in APD I am exploring design aspects of a 3D Environmental Puzzle style game. I am particularly interested in the interplay between game systems which the player can control such as movement of their character, carrying items, using special abilities or resources and game systems which the player cannot control directly but predict to some degree for example, day/night, temperature, wind or non-player character behaviour patterns.

For this experiment I  wanted to test an idea I had to use wind as a component in a puzzle piece where a player might have to observe the direction that toxic gas is blowing in an area and avoid it or wait until a path opens up between areas of gas so they can pass through.

Method

• Set up small scene with ground, gas vent and flag which respond to wind
• Represent wind direction (Vector3) and force magnitude (float) in central wind controller script
  • Change direction and magnitude at random intervals (1-5s)
  • Translate changes into WindZone & Cloth components
• Particle Emitter components to produce toxic gas being released from vents
  • Particle cloud sprite, colour over time, size over time, emission rate, colliders, transparency over time, physics properties
• WindZone component to effect particle systems
  • Direction, magnitude, turbulence
• Cloth component to simulate flag behaviour
  • Pin sections of cloth to flag post
  • Adjust cloth variables including stretch and bend values to get semi-realistic wind effect

Reflection

• Unity Cloth component is buggy and difficult to work with
• Wind Zones don’t effect cloth components so I had to write a script that would bridge the gap between the wind zone/ particle emitter and the cloth component
• I had to design a randomizer to rotate the wind in a way that looked semi-realistic and wasn’t totally random
• Each change in direction is limited to 30° at intervals between 1-5s so if a player were to stand behind the fumes they would have time to move if they noticed the wind change direction
• I am only part way through implementing a player damage system into this scene so that the player can appear to be injured if they stand in the fumes

References

Salen, K. and Zimmerman, E., 2004. Rules Of Play. Johanneshov: The MIT Press.

Latham, CA 2016, Extending Virtual Worlds : Advanced Design for Virtual Environments, CRC Press LLC, London. Available from: ProQuest Ebook Central.