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BIHC- Bio-inspired models of human crowds

Periodic Reporting for period 2 - BIHC (BIHC- Bio-inspired models of human crowds)

Reporting period: 2017-01-01 to 2017-12-31

With current consumer-grade personal computers, it is possible to display 3D virtual scenes with thousands of animated individual entities at interactive frame rates. Crowd simulations are, however, too often limited to characters lacking individuality and wandering in an environment. This situation is particularly problematic in the field of cultural heritage in real-time simulations of the past where the realism of individual behavior is key. In a collaboration across the computer science and the archaeology fields, this project addressed this problem, by exploring bio-mimicking techniques in the development of a generative model for heterogeneity and spontaneity in the behavioral animation of crowds. The project aimed at the development of a framework composed of a behavioral model (drawing on biological and economical tenets) and an associated authoring tool. This was to provide a software architecture for generative crowds and an associated application enabling users from the cultural heritage sector (non-programmers) to easily animate any historic/geographical scenario they may wish.
More specifically, the goals can be defined as i) the development of a bio-inspired model of agency for virtual humans integrating bio-mimicking techniques originating from ALife's framework and known as computational ecosystems, ii) the development of an authoring tool to interact with the parameters of that model and develop context-specific behaviors/animations, and finally iii) the development of a proof-of-concept - the simulation of a historical environment, with the assistance of non-programmers using the authoring tool developed earlier.
Resulting from this project, a new ALife model for virtual populations was developed, and a generative tool, Easy-Population, was produced. This tool follows a drag-and-drop design paradigm, to enable users to create their own populations. This system gives 'anima' to a set of otherwise static characters generating an autonomous and self-organizing population. Based on a set of 3d models (the static characters), and a set of locations (interest points), the system provides spontaneous behaviors and autonomous interactions to the characters. Available behaviors are: walk (with a different number of gaits), walk side by side, stop and chat/ argue/ flirt, and children following adults. It is also possible to configure static elements performing looping behaviors or two-state repetitive actions.
In summary, this project provides a solid framework allowing the creation of generic populations of autonomous and self-organizing virtual humans. Although results obtained were evaluated by the end users of the tool, to achieve the level of realism adequate to historical simulations, the collective behavior component needs further research. In particular, the simulation of cultural aspects of the behaviors. This research opens new investigative routes since differences in human behavior are a fundamental part of the immaterial heritage of the sites represented and simulating culturally driven behavior seems to be paramount in the cultural heritage domain.
"We performed a study on the impact of biological inspired principles used in the simulation of groups and large populations. Results were reported publicly in the paper “Human Crowd Simulation: What Can We Learn From Alife?”, presented in the 15th International Conference on the Synthesis and Simulation of Living Systems (ALIFE XV).
We developed an ALife model, inspired by biological societies, for autonomous populations of virtual characters. Results and model were published in the paper “Bio-Inspired Virtual Populations: Adaptive Behavior with Affective Feedback.” in the 29th Conference on Computer Animation and Social Agents in Conference (CASA2016). An additional video documenting the main features of the model was produced. This AI model was posteriorly refined and simplified, in a trade-off between its complexity and the quality of the generated behavior.
We developed a first case study, the medieval village of Mértola, with integration of the AI model developed animating the population of virtual humans. The case-study took the form of a standalone application of the simulation of the village and it required a) interaction with Arqueologists from Campo Arqueologico de Mértola and b) coordination of work with Professors and Students from FCL, and c) artwork on 3d models. The process of execution of the simulation was reported in the papers “Virtual cities inhabited by autonomous characters: a pipeline for their production”, presented at the 8th International Congress on Archaeology, Computer Graphics, Cultural Heritage and Innovation (Arqueologica 2.0) and ""Animating with a Self-organizing Population the Reconstruction of Medieval Mértola , presented at 15th Eurographics Workshop on Graphics and Cultural Heritage, and “From Self-Portraits To Medieval Simulations: Computational Artificial Ecosystems As Multicontextual Authoring Tools”, presented at the conference Artech 2017. We further have presented this work at the Summer-school Salento VR17.
We have developed a generative tool, Easy-Population, to enable non-programmers from the cultural heritage sector to create their own populations. This tool integrates the AI model in a user-friendly way, following a drag-and-drop design paradigm. It was posteriorly published at the Unity3d asset store, widening the scope of users to other sectors such as the game development and the architecture communities.
We developed a second case study, a neighborhood in medieval Silves, in the South of Portugal. The population of this simulation was generated by the technicians from the Archaeology Musem of Silves, using the software tool developed. The case-study took the form of a) a standalone application allowing first-person virtual visits to the simulated area, and b) a VR application. The VR experience was exhibited at the main tower of the castle of the village, overviewing the simulated site. To build this final case-study, we had to interact with the Archaeologists from the Archaeology Museum of Silves, to coordinate the process of modelling 3d assets with the Professors and Students from FCL, and integrate the researcher’s own art work on those 3d models, landscape and characters.
The overall project was additionally presented next to specialist audiences in two workshops of the H2020 project ViMM (Virtual Multimodal Museum), and the researcher was also invited to present it in a keynote presentation at the Videogames Conference VJ17.

The two case studies produced show autonomous populations that self-organize, expressing heterogeneous and spontaneous behaviors, with individual differentiation of behaviors and emotional expression. These are promising results since, to our knowledge, and to date, there are no populations in cultural heritage simulations that raise the level of expressiveness to such degree. By easing the usability of the model, and its expected wider acceptance and usage, the impact will be an increase on the number of simulations of ancient populations in historical reconstructions, nowadays typically void, or not in real time. The publication in open-access at the Asset store of the game-engine Unity3d, has opened the tools to the broader community, not restricting it to the heritage domain.
Screenshot of case study (Simulation of populated medievel village)