Evaluation of Physically Inspired Models in Video Game Melee Weapon SFX Emil Wallin Audio Technology, bachelor's level 2020 Luleå University of Technology Department of Arts, Communication and Education Evaluation of Physically Inspired Models in Video Game Melee Weapon SFX Emil Wallin Luleå University of Technology [email protected] ABSTRACT This study explored the possible impact to a game’s responsiveness and to players’ preferences by using a physically inspired model (real-time pitch and amplitude modulation) as a means of efficiently achieving responsive variation for melee weapon sound effects in a game using the in-engine audio features. A play test was created were 24 participants (12 with audio engineering backgrounds, 12 without), all with prior gaming experience, played through a game level where they would audition a non-variational implementation of a sword’s sound effects and a variational implementation with the same sound samples being modulated in real-time. The participants did not know what they were auditioning, and in a form filled out after the play test they assessed the differences in the level parts’ responsiveness and their preference. From this form no significant benefit or drawback was found to the game’s responsiveness, and no significance was found to the participants’ preference toward either sound effect implementation. The study’s conclusions are that these physically inspired models could be used as a mean of implementation for melee weapon sound effects if the sounds used or the game setting would suit this approach, or if this would be the artistic wish of the game developers. 2 TABLE OF CONTENTS 1 INTRODUCTION 4 1.1 INDIE GAMES 4 1.2 BACKGROUND 4 1.2.1 SOUND EFFECT VARIATION IN GAMES 4 1.2.2 EXTENSIVE SOUND LIBRARIES 5 1.2.3 LARGE SCALE GRANULAR SYNTHESIS 5 1.2.4 PHYSICAL MODELING 5 1.2.5 INPUT PARAMETERS OF A PHYSICALLY INSPIRED MODEL 6 1.2.6 THE MELEE WEAPON SOUND 6 1.2.7 OUTPUT PARAMETERS OF A PHYSICALLY INSPIRED MODEL 7 1.2.8 DEFINING RESPONSIVENESS 7 1.2.9 UNREAL ENGINE 4 7 1.3 PURPOSE AND RESEARCH QUESTION 8 1.3.1 REALISM IN VIDEO GAMES 8 1.4 HYPOTHESIS 9 2 METHOD 10 2.1 TOOLS 10 2.1.1 SOFTWARE 10 2.1.2 HARDWARE 10 2.2 SOUNDS AND IMPLEMENTATION 10 2.2.1 ADDITIONAL SOUNDS 11 2.2.2 IMPLEMENTATION OF THE PHYSICALLY INSPIRED MODEL 11 2.2.3 BEFORE PRE-STUDY 12 2.3 PRE-STUDY 12 2.4 MAIN STUDY 13 2.4.1 THE GAME 13 2.4.2 THE QUESTIONNAIRE 16 2.4.3 DEMOGRAPHICS 17 3 RESULTS AND ANALYSIS 19 3.1 RESULTS 19 3.2 DATA ANALYSIS OF THE RESULTS 20 3.3 DEMOGRAPHIC DATA – ANALYSIS 24 4 DISCUSSION 26 4.1 THE RESULTS 26 4.2 FROM PRE-STUDY TO RESULTS 26 4.3 RESPONSIVENESS 26 4.4 PREFERENCE 27 4.5 COMMENTS BY SUBJECTS 27 4.6 EXPERIMENT METHOD AND POSSIBLE ERROR SOURCES 28 4.7 OTHER USES FOR PHYSICALLY INSPIRED MODELS 29 4.8 ECOLOGICAL VALIDITY 29 4.9 FUTURE RESEARCH 29 4.10 SUMMARY 30 5 ACKNOWLEDGEMENTS 31 6 REFERENCES 32 APPENDIX A 34 APPENDIX B 38 3 1 INTRODUCTION The problem of variation in video games has been a point of interest since the hardware became capable of using big sound libraries and real-time synthesis. In the last decade these tools have also become accessible to game developers with small or no budget, but it has not yet been utilized to its full extent. The proposed research investigates the use of simple physical modelling, called physically inspired models, in video games and its possibilities regarding melee weapon sound effects, and in turn its use in indie game-development. This project will amass data from a questionnaire after a play test were a game level will be presented to test subjects who then play through different parts of the game level which utilizes different ways of implementation, and the participants later answer questions about the audio. 1.1 INDIE GAMES The last decade has seen a huge rise in indie-game sales and success, and some would argue that many of the best games of the decade 2010-2019 has been indie-titles. On Forbes’ “The Best – And Most Important – Video Games Of The Decade”-list (Kain, 2019) we see titles like Hotline Miami (Dennaton Games, 2012), Hollow Knight (Team Cherry, 2017), and Journey (Thatgamecompany, 2012) on the same list as big-studio titles (AAA titles) such as Grant Theft Auto V (Rockstar Games, 2013). The success of indie-games has brought forward certain aesthetics which are often featured through-out many titles. Most indie-titles tend to be limited in their graphical capabilities and instead prosper in their use of aesthetic choices such as being 2D, either utlizing side-scrolling or top-down-view, and using designs inspired by retro gaming, either by the use of pixel-art, or the use of mechanics made popular by 90’s games. This inspiration has affected the sound design of these games as well, with many games using chiptunes and pulling inspiration from the limited sound capabilities of early 90’s consoles, or by simply having limited sound effect variations. A big factor in this limitation is also the lack of sound designers on indie-teams – why have many mediocre sounds instead of one good and fitting sound? This is where physical modelling could help either the indie-developer designing their own soundscape or the lone sound designer creating sounds on no budget. 1.2 BACKGROUND 1.2.1 SOUND EFFECT VARIATION IN GAMES Video games have been under limitations of the hardware for most of its existence. In 2012 the eighth generation of video game consoles radically improved performance of consoles and made experiences on console and PC more similar, which in turn made it possible to increase both the used storage space of audio and the workload of audio engines. (Kypreos, 2018) (Loveridge, 2019) The improved conditions of audio performance led to an even bigger emphasis on avoiding audio repetition, but as Vachon (2009) mentions some sounds are accepted as repetitive, most notably non-diegetic sounds of menus and HUDs. However, there is also mention of how non-repetition is specifically beneficial to fighting sounds as a fighting mechanic is often a big part of the games in which it is included. (Vachon, 2009) Stockselius (2018) conducted a study comparing repetitive and non-repetitive sound design for video games where all parts of the game’s audio were either repetitive or non-repetitive. The results showed a general negative impact of repetitive sound design, and that the second most noticeable repetitiveness of the sound design was the “karaktär” (character) category which included foley 4 and SFX (in this case gunshots). (Stockselius, 2018) This further establishes the importance of variation of SFX in games. Vachon (2009) mentions a few methods to avoid annoying repetition in games. For example, the large scale granular synthesis, the use of physical modeling, and the more obvious extensive sound library approach. These are all viable methods of achieving variation, however in the context of low-budget video game development many of them might not be achievable as the limited number of sound designers and the lack of time makes recording, designing, and implementing some of these approaches impossible. 1.2.2 EXTENSIVE SOUND LIBRARIES Recording and designing a large amount of sound samples has its share of both pros and cons, however it is the most obvious solution to avoiding annoying repetition in games. A large pool of sounds for a single sound effect gives the sound designer full control of every single sound option, ensuring that every sound keeps a certain level of quality. However, the large scope of modern games means the sound designers would have to collect and create a huge amount of sounds for a large number of events resulting in a big economical strain from both recording/buying samples, but also from the sound designers’ workload increasing drastically. (Vachon, 2009) A big sound sample library would also mean that more data would have to be loaded into the unit’s RAM, which both takes time and occupies space that might be required by other parts of the game. (Vachon, 2009) 1.2.3 LARGE SCALE GRANULAR SYNTHESIS Large scale granular synthesis is a phrase used by Vachon (2009) which uses the concept of granular synthesis but with bigger grains. Vachon’s (2009) “large scale” concept can be used by separating a sound based on time and/or frequency content. For instance, Jacobsen (2018) mentions how a door opening was split into “door handle, “swing of the door”, an optional “swing sweetener”, and “end of opening” and by separating five original door sounds into these basic characteristics which were later randomly summed in the game engine the game would contain 625 variations of a simple door sound. This creates a greater amount of variation within a limited group of samples, whilst simultaneously using less RAM by not having to load a bigger audio library (which would be the result of summing the separated sounds in advance). (Vachon, 2009) In practice a melee weapon sound effect could be separated into categories such as “aerodynamics”, “impact low end”, “impact high end”, “material impact texture”, and “resonance”, where several of the sounds could be taken out of context-dependent sound pools. 1.2.4 PHYSICAL MODELING Physical Modeling is described as using parameters of the game engine to synthesize sounds which are in direct relation to the actions of the player.