GAME VU DEVELOPING A MASTERCLASS FOR HIGH SCHOOL STUDENTS USING THE HALF LIFE 2 SDK A Eli ns S V Bhikharie Intelligent Multimedia Group Department of Computer Science Vrije Universiteit De Boelelaan 1081 1081 HV Amsterdam Netherlands E mail eliens cs vu nl KEYWORDS game development Half life 2 SDK education ABSTRACT In this paper we will describe our experiences with developing a masterclass game development for 14 16 year old high school students at the Vrije Universiteit Amsterdam For the masterclass we developed a game using the Half Life 2 SDK called VU Life 2 for which we created a realistic level covering part of the faculties premisses as well as a simple assignment of a non violent nature that the high school students had to complete before developing their own variation on a game level Our experiences indicate that the moderately complex task of developing a game level using the Half Life 2 SDK is feasible provided that the instructions and assignments are sufficiently well focused INTRODUCTION In june 2005 we started with the development of a game nicknamed VU Life 2 using the Half Life 2 SDK We acquired a Cybercafe license for Half Life 2 with 15 seats because we would like to gain experience with using a state of the art game engine and we were impressed by the graphic capabilities of the Half Life 2 Source game engine After some first explorations we set ourselves the goal to develop a game that could be used for promoting our institute and to prepare a masterclass game development for high school students Our first ideas concerning a game included a game in which the subject chases a target a game where the subject has to escape and an adventure game In the end we decided for a less ambitious target namely to develop a game which gives the subject information about our institute by exploring a realistic game environment representing part of our faculty As an incentive a simple puzzle was included which gives the subject information on how to obtain a hidden treasure to be found in a specific location in the game environment See the next section for more information on this With only about eight months time we decided to do a feasibility study first to gain experience with the Half Life 2 SDK technology and to determine whether our requirements for the game and the masterclass could be met For the VU Life 2 game we can summarize our requirements as follows the game must provide information about the faculty of sciences of the VU the game environment must be realistic and sufficiently complex and the interaction must be of a non aggressive non violent nature The last requirement has to do with the fact that the VU is by its origin a Christian university so that any agressive or violent interaction could hardly be considered to be an appropriate theme for a promotional game For the masterclass we stated the following requirements it must be suitable for beginners in particular high school students it must explain basic texture manipulation and offer templates for modifying a game level and finally there must be a simple easy to understand manual The format for a masterclass for high school students at our institute is three times two hours of instruction The goal is to attract more students for the exact sciences However if the masterclass would be too complex we would run the risk to chase potential students away which would be highly counter productive In this paper we will report our experiences in developing the VU Life 2 game and the associated masterclass The online information for the masterclass including all documentation can be found at www cs vu nl eliens masterclass The structure of this paper is as follows We will first give an impression of the VU Life 2 game by presenting a typical usage scenario In the sections that follow we will discuss the technical issues encountered in developing the VU Life 2 game and the assignments for the masterclass Then we will moreover describe the documentation we developed for the masterclass and discuss the lessons we learned in particular our experiences in presenting the masterclass to high school students Finally we will draw our conclusions by giving a summary of our efforts and indicating our plans for the future Figure 1 Opening Screen VU Life 2 For a general overview of the issues in game development and design see Juul 2003 and Sherrod 2006 VU LIFE 2 THE GAME To give an impression of the game and how we used the Source game engine and the associated Half Life 2 SDK let s start with a typical game scenario illustrated with a walkthrough Figure 2 Lecture Room When starting VU Life 2 fig 1 the player is positioned somewhere in the game environment such as a lecture room fig 2 In the front left corner of the lecture room middle right of fig 2 there is a place marked as an information spot The information spot corresponds with one of the nine squares in the top right of the screen The player is expected to detect this correspondence by exploring the game environment The nine squares together form a puzzle indicating when all squares are filled where the hidden treasure can be found In other words when the player visits all the nine information spots contained in the game environment the player has solved the puzzle and may proceed to obtain the hidden treasure To visit all the information spots the player has to explore the game environment including another lecture room the student administration office fig 3 and the student dining room While exploring the game environment the player may read information about the curriculum meet other students and encounter potentially dangerous individuals As illustrated in figs 2 3 the puzzle squares will gradually become filled and when complete the combined puzzle squares will indicate the location of the hidden treasure which is the 7th row of chairs of the other lecture room Figure 3 Student Office Despite the fact that we intended to create a non violent game we must admit that the hidden treasure actually consists of obtaining the power to use weapons From our observations and this was exactly what motivated us to include this feature the use of weapons proved to be a most enjoyable aspect for the high school students playing the VU Life 2 game in particular when allowed to play in multi user mode USING THE HALF LIFE 2 SDK TECHNICAL ISSUES The VU Life 2 team had no prior experience with the Half Life 2 Source SDK Therefore we started by exploring three aspects of the Source SDK level design with the Hammer editor making game modifications and importing custom models into Half Life 2 During the exploration of these aspects we came across various technical issues which we will discuss below Level design First we made various smaller levels Each level was compiled and tested seperately so that it worked fine as a standalone level The idea was to combine them that is to create one large world containing the smaller levels However the initial coupling caused several compiling errors After analyzing the errors some important restrictons for building large levels became clear In the second part of the level compilation process called VVIS a visibility tree of the level is made This tree is used to tell the renderer what to draw from a given player viewpoint in the level The amount of used brushes the default shapes for creating a level determine the size of the visibility tree The bigger the tree the longer VVIS will take to build the visibility tree at compile time and the more work the renderer has to determine what to draw at runtime Therefore the standard brushes should only be used for basic level structure All other brushes that do not contribute to defining the basic level structure should be tied to so called func detail entities This makes VVIS ignore them so that they do not contribute to the visibility tree thus saving compiling and rendering time In addition there is a hardcoded maximum to the number of vertices faces you can use for a level Each brush based entity contributes to the number of vertices used It is possible however to reduce the number of vertices used by converting brush based objects to entities This is done outside of the Hammer level editor with the use of 3D modelling software and the appropriate conversion tools With the above mentioned restrictions in mind we were able to create a relatively large level that more or less realistically represents the faculty of exact sciences of the VU campus The key locations are as partially illustrated in figs 2 3 the restaurant lecture room S111 fig 2 lecture room KC159 the student office fig 3 and the multimedia room S353 not shown To give an impression of the overall size of the VU vmf game level as map information we obtained 6464 solids 41725 faces 849 point entities 1363 solid entities and 129 unique textures requiring in total a texture memory of 67918851 bytes 66 33 MB Game modifications Since a multi user environment was required we chose to modify the Half Life 2 Deathmatch source code The biggest challenge for modifying the code was finding out how to implement the features for VU Life 2 To this end relevant code fragments were carefully studied in order to find out how the code is structured and works Furthermore by experimenting it was possible to get the features working Below is a list of features for the VU Life 2 Mod Player properties Players start out immortal meaning that they cannot die while exploring the world Furthermore continuous sprinting is enabled which allows the player to walk around faster Puzzle HUD When the player starts out the puzzle HUD is the only HUD element displayed Puzzle setter Allows puzzle parts to be displayed on the puzzle HUD Weapon enabler Allows weapons to be enabled disabled for the player Enabling the weapons also enables damage and switches from the puzzle HUD to the default Half Life 2 HUD which displays weapon and damage information along with a crosshair Importing models Getting a model into the Half Life 2 environment requires two steps The model must be exported to the custom Valve format smd The model must be compiled from smd to mdl format The first step required finding the correct plugin that allowed a conversion to the smd format The second step required using Valve tool studiomdl and defining a qc file which is used to specify properties for the compiled model The default Valve tool studiomdl exe proved to be difficult to work with because it requires a lot of parameters have to be set By using the StudioMDL 2 0 GUI compiling the smd file was very easy It sets the appropriate parameters allowing the user to focus on the compiling of the model THE MASTERCLASS INSTRUCTION AND ASSIGNMENTS The masterclass consisted of three sessions two hours each In the first session the high school students were given an overview and general instructions on how to accomplish the assignments and were then set to play the VU Life 2 game Figure 4 Masterclass Room The assignments as already indicated in the introduction were 1 to modify an existing game level by applying different textures see fig 4 2 to create objects within an existing game level and 3 for advanced students only to create a new level More complex assignments such as creading a Mod were considered to be outside of the scope of this masterclass The overview and instructions given in the first session included an overview of the history of games a general introduction on modelling characters and objects the use of the Hammer editor and finally an explanation of the assignments The history of games encompassed historic landmarks such as Pong Tetris and The Sims as well as a brief discussion of current games like Worlds of Warcraft and Half Life 2 In the introduction on modelling an overview was given of the major tools like Maya and 3DSMax as well as a brief explanation of notions such as vectors polygons textures lights and skeleton based animation Both the explanation of the use of the Hammer editor and the assigments were explicitly meant as a preparation for session two in which the students started working on their assignments Figure 5 Texture Conversion Tool In addition to the oral overview and instructions the students were given a manual that was made available in paper as well as online to prepare themselves for the assignments The homework for the second session was to make pictures suitable for the application as textures in the masterclass room which is depicted in figs 4 and 7 To allow the students to easily apply their textures a texture conversion tool fig 5 was offered that converts and image file into a texture for a particular location in the game level based on keywords e g mc floor for the texture on the floor of the multimedia room Alternatively the students could use the VMT Edit tool fig 6 and apply the texture using the Hammer editor figs 7 and 8 Figure 6 VMT Edit Tool The introduction on how to use the Hammer editor covered the basic tools including the block tool for creating simple object selection tool to select objects for texturing entity tool to select dynamic or interactive objects and the texture tool to apply textures to an object as well as how to compile a level into a map ready for play including an explanation of the BSP world VIS visibility and RAD radiosity components Figure 7 Masterclass Room in Hammer Editor The students were explicitly told that the assignments did not involve any programming creating game AI or modelling To learn these aspects of game development they were simply adviced to sign up for our curriculum Instead we told them use your phantasy and be creative Figure 8 Changing The Camera LESSONS LEARNED In the second session the high school students started working with great fervour Somewhat surprisingly all students worked directly from the paper manual rather than consulting the online documentation or the help function with the tool In retrospect what appeared to be the main difficulty in developing the masterclass was to create challenging assignments for every skill level In our case the basic skill level modifying textures of a template level allowed the high school students to start immediately By having optional advanced assignments like creating your own objects you can keep all students interested since there are assignments to match the various skill levels Competition To stimulate the participants in their creativity we awarded the best result according to our judgement with a VU Life 2 T shirt and a CD with Half Life 2 The results varied from a music chamber a space environment a Matrix inspired room and a messy study room We awarded the Matrix room fig 9 with the first prize since it looked although not very original the most coherent CONCLUSIONS In this paper we reported our experiences in developing a moderately complex game environment and associated masterclass for highschool students illustrating the effort needed to develop such an application in an educational setting indicating technical constrain
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