CROWD SIMULATION AS A SERVICE

Transcription

1 CROWD SIMULATION AS A SERVICE Client dr. Roland Geraerts (r.j.geraerts@uu.nl) Virtual Worlds Dept. of Information and computing sciences Utrecht University (version ) Screenshot of a crowd simulation with 10K robots (and 1 human), produced in the previous software project in which students (GentleMelon) developed a Unity3D plugin. See for the full movie.

2 INTRODUCTION A huge challenge is to simulate tens of thousands of agents (e.g. characters, robots, pedestrians, or monsters) in real time where they realistically avoid collisions with each other and with obstacles present in their environment, especially near narrow passages where cooperative behavior is required. This environment is usually three dimensional, e.g. it may contain bridges where agents can walk over and under as well. The environment can also dynamically change, e.g. a bridge may partially collapse. We 1 study how we can automatically create a data structure that represents the walkable surfaces in virtual environments, and how this structure can be updated dynamically and efficiently when the environment changes. We refer to this structure as a navigation mesh, which is a decomposition of the walkable surfaces into simple, non overlapping shapes. See Figure 1 (left) for an example. This mesh enables efficient crowd simulation, which is our topic of research. We study and develop a crowd simulation framework and its components, which ranges from global (AI) planning to local animation, see Figure 1 (right). We create models for realistic crowd behaviors, which includes studying how (groups of) agents move and avoid collisions in such environments. We continuously integrate our research into our UU Crowd simulation (UUCS) software which is used by many research institutes and companies. We run simulations in realistic environments and game levels to study the effectiveness of our methods. In this project, you will build a Software as a Service solution for real time, interactive, massive crowd simulation applications. SIMULATION FRAMEWORK To allow for efficient and flexible crowd simulations, our simulation framework consists of the following five levels of planning: FIGURE 1. (Left) A multi layered navigation mesh. (Right) A five level hierarchy for path planning and crowd simulation. 1 Crowd simulation members of the Virtual Worlds group (Computer Science, Utrecht University) are Roland Geraerts, Wouter van Toll and Arne Hillebrand, and many MSc students who are involved in projects.

3 High level planning: Agents determine their global actions, and each action results in a geometric path planning query (i.e. move from point A to point B ). In this phase, we support for instance social groups, large groups, re planning of agents when the navigation mesh changes or when crowd densities change. Global route planning level: Given the start and goal position of an agent (or a group of agents), we compute a so called indicative route that the agent (or group) should globally follow during the simulation. Our navigation mesh can generate various types of indicative routes, such as short paths with some amount of minimum distance to the obstacles, or paths that avoid areas with a high crowd density. Indicative routes can also be optimized for camera movement or stealth movement. Route following: In each simulation step, the agents compute an attraction point on their current indicative route, and they compute their preferred velocity (i.e. their preferred walking speed and direction). We have also developed a route following method that allows agents to have personal preferences for different terrain types. Local movement: In each simulation step, each agent converts its preferred velocity to an actual velocity that adheres local rules. These rules include resolving collisions with other (moving) agents, avoiding possible future collisions, adapting the velocity to the local crowd flow, and maintaining coherent social groups. When all velocities have been computed, the agents apply their velocity for one simulation step, and the next step begins. Animation: In many applications, the crowd should be visualized smoothly in real time. In our model, this task is delegated to Unity3D which offers sophisticated 3D animation and rendering. More information about the framework can be found in Chapter 10 of Wouter van Toll s PhD thesis on Navigation for Characters and Crowds in Complex Virtual Environments 2. API AND UNITY3D PLUGIN We have compiled the UUCS software as a DLL plugin that can be linked to other programs, such as the Unity game engine. Unity can communicate to this DLL via an API that exposes the most important UUCS functionalities (e.g. add a character at position X, let character Y plan a path to position Z, and so on). In the predecessor of this software project, students have created a Unity3D plugin which allows them to build interactive applications, see Figure 2 and 3 on the next page. This plugin allows developers to easily create interactive applications. The corresponding manual, tutorials and API reference can be found here: The problem with this solution is that it doesn t scale well (e.g. simulating 10K agents on a 4K display with 60fps is not possible yet in real time), it doesn t support other devices than Windows PC s, and doesn t allow running multiple simultaneous simulation instances phdthesis

4 FIGURE 2. Screenshot of the Unity3D plugin for crowd simulation as developed by GentleMelon in the predecessor of this project. Unity3D plugin Unity C# scripts C# wrapper (API) UUCS: DLL and API in GUI (C# scripts) Documentation Tutorials FIGURE 3. Global design of the Unity3D plugin (by GentleMelon). PURPOSE The goal of the project is to design and build a Software as a Service 3 solution for real time, interactive, massive, secure, and concurrent crowd simulation applications on any device. Real time means that the solution can simulate many agents in real time (typically up to 50,000 agents) without stalls. The solution should handle interactive requests by the user, so it should have a low latency (as if the engine 3 See for a global overview of SaaS.

5 would run on the user s own machine). Security and privacy of users and their data should be safeguarded. The system should be able to handle concurrent users. Applications may run on any device (e.g. an ipad, PC, or web browser). All of the software pieces need to be well designed, implemented and tested. At the end of the project, the prototype, demos and tutorials need to be ready to be distributed to the targeted users, including game developers, developers simulation and training applications, students and researchers. WHAT S THE FUNCTIONALITY OF THE GAME/ AND/OR SOFTWARE? The SaaS solutions needs a web host, a (cloud hosted) simulation master server and simulation slave servers. Clients should be able to connect to the web host. A Unity3D client should be created based on the Unity3D plugin. The 10K robots example project must be extended and demonstrated in real time on a fast laptop. Finally, you need to create materials for PR purposes, as well as ample documentation as well as some tutorials. UNITY3D CLIENT The SaaS solution need to be demonstrated in a light weight Unity3D client, which should have the same functionality as the Unity3D plugin while calls to the Windows DLL are replaced by calls to the web host. Light weight means that the code base should be minimal, and should compile to any Unity3D supported device (such as a PC, ipad, or Android Phone) or webpage. (CLOUD HOSTED) SIMULATION MASTER SERVER The web host takes care of a database and network functionality and should provide an API for authentication of users; hosts clients in case of a web client; a database for managing user data and credentials, for usage data mining (and perhaps for storing simulation history and parameters); a connection API to server external clients. The web host talks to a back end simulation master server. (CLOUD HOSTED) SIMULATION MASTER SERVER The simulation master server can be a fast machine 4 or (eventually) a cloud solution offered by the university. This server runs networking software; 4 In the project, you can play with our PC with two Intel Xeon E v3 12 core processors and 32GB of DDR4 ECC RAM.

6 takes care of load balancing; takes care of load distribution; executes simulations in parallel (e.g. consider a base simulation where one parameter is varied in each individual simulation, such as the number of characters that are spawn at a certain point. The server can spawn (or run) one or more slave servers. It may be good to know that OpenMP is used to make the simulation run in parallel. A performance boost can be further obtained by splitting the environment into some blocks (where each block is given to a certain computing node). An initial (MPI based) implementation has been created by PhD student Arne Hillebrand. The simulation slave server SIMULATION SLAVE SERVERS runs actual simulations (using the DLL); provides an API; is created on the fly; is possibly virtual. Please also add a function in the API (or modify an existing one) which allows the user to get back the results (e.g. the characters positions) in a certain (rectangular) view. This is important for efficiency reasons, e.g. when a city center of many square kilometers is simulated, you may only need to report the results in a certain screen view. 10K ROBOTS EXAMPLE In this project, implementing the above architecture should have the highest priority for the computer science students. The artists should work on the following demonstrator, based on the 10K robots example project (see the Art pipeline documentation of the GentleMelon software project). This demo should be overwhelming, with lots of effects, more types of characters, more explosions and more dynamic changes in the environment. This means that the artists need to work on more moving characters, special effects and textures. Also, some time needs to be spent on making the animations more CPU efficient (e.g. by using GPU instancing of the animated models, by using different levels of details of the models, etc.). This project should be converted so that it works with the Unity3D client (on an MSI laptop: MSI GS73VR 7RF 213NL STEALTH PRO 4K with an Nvidia GTX 1060 graphics card). Demonstrate that this plugin now is platform independent (by showing that this project runs on multiple types of devices). Preferably, the demo should run in real time. If that s not possible, tune the demo (with fewer robots) so that it runs in real time.

7 DOCUMENTATION AND TUTORIALS We want to help the end user by providing him/her a set of tutorials and demos to decrease the learning curve of using our software and to teach them about the software s possibilities. Please write a (well formatted) document about the design of the software you have created; create a tutorial explains how to build a client application. Please prepare the following items for PR reasons (NB items should be put on an internal webpage, targeted at the end user, which is not visible for the outside world): PR Put the tutorials and Unity3D demo on a well formatted web page; Create a professional and an impressive movie (4K, 60fps, low compression) (not necessarily in real time) for marketing purposes, as was done in the predecessor of this project, see The application area is crowd simulation. APPLICATION AREA The software is used in research and education by many research institutes, including ours. In our department, the plugin is used in the course Crowd simulation 5. See this overview 6 for projects we ve been doing using the crowd simulation software. The plugin can be used in many commercial areas, including the serious and entertainment gameindustry (e.g. crowds in applications used for training or in architectural applications, or in computer games), the safety and security market (e.g. to perform evacuation studies in big infrastructures, to study crowd flow optimizations in cities, or to real time predict agents motions during an event), and simulations in the intelligent transport sector. We are currently initiating an academic startup, and the results of this project can be used here (if our university provides a license for that.) CONTEXT/RELATED WORK The related work is already described above. Most relevant are the results of the previous software project (Unity3D plugin). 5 See for the course description. 6 See for a list of outreach activities, and for for an overview of our crowd simulation research and development activities.

8 WHY IS THE PROJECT INTERESTING? Crowd simulation is an important AI component in many games and simulations, but we think that its current state of the art can be dramatically improved. It is not only a challenging topic, but there also appears to be many errors and design mistakes in existing algorithms. Consequently, NPCs get stuck, walk through each other, or react in an undesired way on dynamic changes in the environment (like a parked car). Also, some algorithms are too slow when many NPCs are presented simultaneously. See for example or for a visual impression. This project may also push some boundaries with respect to interactive SaaS solutions. By creating a user friendly and high quality SaaS solution, we allow developers to facilitate high quality, real time and demanding crowds in less time. It will improve the gameplay and immersion in games, and will bring a more realistic crowd simulation solution to developers of other application areas. Our engine is already used for some projects, including crowd flow optimization for the Tour de France in Utrecht and evacuation studies in the Noord/Zuidlijn in Amsterdam. The software contributes to the safety in such areas. From a commercial perspective, we hope we can generate more revenue to finance R&D. WHY IS THE PROJECT INTERESTING FOR THE STUDENT? Students learn to deal with and develop advanced (game)technology, i.e. crowd simulation, SaaS and cloud architecture and Unity3D. Crowd simulation in games and simulations can still be improved a lot, and a big improvement in this field shows that you have much to offer. So this project is a nice one to have on your CV/portfolio. Optionally, we can pay a visit to a company that uses the software. Also, I tend to make lots of advertisements of your work. For instance, project results are still shown on the video wall (of the KBG), and are shown in the TV show De kennis van nu 7. Furthermore, they are demonstrated at many conferences and to many companies. You need to deliver the following items: DELIVERABLES The items in the section `What s the functionality ; A document with the description and choices of the SaaS solution; Unit tests. For instance, you could use All software, sources, assets etc need to be put on the UU GIT server and on a USB stick. 7 See

9 DURATION PROJECT The project takes place during period 3 and 4 (week 6 through 26, so through ). DESIGN BOUNDARIES In general, we find light weight, beautiful, extendable, maintainable and efficient code very important. NB many code you provide will be directly exposed to the end user. More specifically: Unity3D is heavily component based. So the design of the wrapper classes should follow the component based paradigm of MonoBehaviour scripts. Unity s own NavMeshAgent 8 9 and NavMeshObstacle are examples that follow this design paradigm. Don t change our API headers/documentation. You re highly encouraged to suggest changes though. We find it always more important to have fewer features that fully work and are of high quality, than to have more features that are incomplete. So please finish a certain feature completely before you move on to the next one. NB Obviously, you can do things in parallel. Work in many iterations. While your project is running, our engine is periodically improved and a few features may be added. LIMITING CONDITIONS Here are some limiting conditions: The software needs to be run on an installation of the 64 bit version of the Unity editor, version or higher. Unity3D uses C# and our core DLL uses C++. The development needs to be done on the UU GIT server. Access can be arranged by sending your list of UU addresses to your client. The UUCS engine is currently only supported for Windows. n.a. SYSTEM INPUT 8 NavMeshAgent.html NavMeshObstacle.html 11

10 DESIRED BEHAVIOUR The user should have a very positive experience when he/she uses the software, documentation, demo projects and tutorials. We hope that developers are positively surprised and impressed by the new possibilities and quality of the software. UNDESIRED BEHAVIOUR The user shouldn t feel frustrated when he/she uses the software. USAGE The number of clicks to get something done should be minimized. The GUI should be consistent. VISUALISATION The user should also see a convenient and clean GUI. The demo should represent the next generation games / simulations. ARTWORK There is a high need for two graphically educated people. They need to work on a movie and 3D assets (and 2D textures) that are needed for the movie. Not applicable. PLAYER S/USER S PERSPECTIVE ACTIONS / OPERATIONS The user should be able to set up an application/client quickly. See above. REQUIRED MATERIALS TEST ENVIRONMENT The final code and projects needs to run without compilation errors and warning on the client s computer (MSI laptop) and on the fast (mentioned) PC.

11 CONTACT PERSON The crowd simulation research is led by Roland Geraerts, see He is your client, and you have to report to him. He s working with some people who are also important for your project, because they have co developed the software and plugin. See the table below for more information. Name E mail Expertise Roland Geraerts (Assistant professor) Wouter van Toll (Lecturer and scientific programmer) Arne Hillebrand (PhD student) Chrit Hameleers (GMT MSc student) R.J.Geraerts@uu.nl W.G.vanToll@uu.nl a.hillebrand@uu.nl chrithameleers@hotmail.com Crowd simulation and game technology Crowd Simulation Engine Unity3D plugin Parallelization SaaS Dionysi Alexandridis (GMT MSc student and scientific programmer) Jan Martijn van der Werf (Assistant professor) dionysialex@gmail.com J.M.E.M.vanderWerf@uu.nl Unity3D plugin Software architecture