Abstract

LegionARius will be a multiplayer real-time strategy game using augmented reality (AR) to let players experience Roman and Germanic history in their own home. Being rooted in the tradition of serious games (SG), LegionARius aims at providing historically accurate knowledge about ancient everyday life in an entertaining manner. The players have to decide the destiny of a Roman cohort or a Germanic tribe living alongside the fortifications of Limes during the second century AD. As Roman commander or chief of a Germanic tribe they build, produce, trade and use their real environment to choose a path between peaceful coexistence and war.

Historical Background

LegionARius plays during the second century AD. In the year 15 AD, Roman armies initially crossed the Alps in order to occupy considerable parts of today’s territory of Bavaria. Before the first half of the first century, these areas were incorporated as province Raetia into the Roman Empire. From the late first century on, the Romans established a permanent occupation of the territory. These troops lived in military camps, constructed by themselves, which differed considerably in size, the degree of fortification, camp internal infrastructure and the number of accommodated soldiers.

During the second century AD the Romans started to fortify the northern border of the empire against the “Barbarians” in the north. They tried to protect it with watchtowers, earth banks, ditches, wooden palisades and stone walls. This so-called Limes (lat. path, border) was more than a military bulwark. It was permeable and flexible, intended to control people and goods crossing it in both directions.

On the other side of Limes the Germanic tribes lived in their settlements comprising multiple long-houses (for families and livestock), grain silos, craftsman's facilities, meadows for grazing cattle and cultivated fields. In contrast to the Romans, these tribes produced their food on their own and through this had a logistical advantage. If uniting the Germanic clans were able to outnumber the Roman "occupying" forces. This is why Roman diplomacy tried to divide the clans to their own advantage.

Project Description

LegionARius is being developed using the Unity cross-platform game engine. For now, all augmented content is handled using the Vuforia Engine. The game is played on a marker or image target that hosts a virtual ground plane on which camp buildings can be placed and manipulated via touch. We create low-poly, but historically accurate 3D models based on archaeological findings. While a prototype about the erection of a Roman military camp already exists, developing the possible establishment of a Germanic settlement was part of this Guided Research. Some of the knowledge provided about the historical buildings is being transferred via game-play, other information in the form of audio texts. The Roman game part is divided into two chapters: Chapter I deals with the first development stage of every Roman military camp, the so-called field or marching camp. Chapter II is about the so-called castrum, the Roman military camp designed for longer periods of time. 

Finally, we decided to use AR to present our content to the player to leverage a few advantages unique to this technology. It is able to melt together the player’s close environment with the game content, without locking out reality completely. What’s more, we think that the relation between the user and the 3D-content, conceived via a portable device, gives an feeling of interaction, more "real" than a traditional computer game ever could convey. This goes for the direct manipulation of augmented game objects on the players' real desk, by just touching them through the display with their fingers. Here the immediate feedback of the virtual and animated content also plays a key role, as well as additional information shown next to the augmented objects.

In addition, we created the foundation-stone for the Limes fortifications, the watch towers, which can be erected by the Players deciding to take the Roman's side. There will be the possibility throughout the game, to customise and extend buildings. Therefore, we here also created several expansion stages for the watch towers. Starting from simple wooden scaffolding towers, the players can upgrade over half-timbered to stone towers.

In comparison to the Romans, historical sources on Germanic tribes are rather limited. In this initial stage of development, we rest the reproduction of the Games' Germanic buildings on archaeological excavations near Feddersen Wierde. There it was possible to reconstruct the history of a whole antique Germanic peasant village, over a period of about 500 years (starting 50 B.C). As a step up from the first version of the game, we also tried to not only reconstruct the buildings facades, but also their interior. Playing the AR-version of LegionARius, it will be possible to take a look inside each building by only coming closer to the models with the gaming device.

The Germanic settlers lived in houses, which were approximately 20 metres long, 5-6 metres broad more than 2.4 metres high. In comparison to the Romans, they particularly used transient building materials, which resulted in the need to rebuild their dwellings after one or two generations. This relatively simple construction method (e.g. there were no nails needed) had also advantages, because it enabled them to build their houses over a time frame of a few weeks only. The 1.5 high walls were made from widow or hazel rods winded around poles rammed into the ground. Upright oaken posts were fixed into holes into the soil, which were prone to draw humidity from the ground and rot over time. These wooden pillars carried the roof truss, which was covered with a thatch roof. The peasant family lived together with its livestock in the same building. The rear part of the dwelling was meant for the barn accommodating about 20 cows. The settlers prepared the ground inside the buildings with dried manure, which protects them from ground water and cold.

In order to leave the Germanic dwellings there were 3 entrances, one on both long sides and another one on rear short side leading into the barn. The threshold was anchored with wooden nails into the ground and on both sides, poles bordering the low doors. Around the houses the inhabitants made ditches into which manure channels flowed directly from the barns. The settlers also build drainage ditches, fences and roads between the houses. In order to illustrate these settlements, we created a first prototype 3D-model of the Germanic settlement to see the dwellings in context of the landscape, their surroundings and neighbouring houses.

We are striving to also deepen the economic cycles encountered during the game. An example for this kind of extension of the gaming experience is the Germanic metalworking and craftsmanship, which could be verified during the archaeological excavations cited above. The main fuel used by the Germanic tribes was charcoal, which could be produced by themselves from wood accessible anywhere. In principle there are different ways to build charcoal kilns. In LegionARius players will be able to produce charcoal using a long stack. Charcoal was for example used for making pottery by baking clay in kilns with round stone cupola. Another use case was the working on iron ore and melting of bronze.

Future Work

In order to provide knowledge in an immersive setting, we want the players to be engaged with the historical content as much as possible. The four pillars we try to rest the player’s attention upon are storytelling, recent AR technology, social interactions and identification through individualisation. To create this immersive experience we are going to extend already existing and build new sub-systems on top, the player interacts with. These gameplay mechanics let the player face historical events, mine raw materials and erect buildings, produce goods and trade them, supply food and water to her/his subordinates as well as pursuing goals by applying diplomacy or force.

Future Evaluation

Due to the fact, that LegionARius is a multi-player game expecting up to four players to sit around a table and the obvious restrictions imposed on us by the Covid-19 pandemic, we were not able to carry out a survey yet. A remote survey was not possible either, because we then would loose the "laboratory conditions", if not being able to reliably monitor the execution of the experiment.

Generally, we are interested in answering two major questions with LegionARius: First, we want to examine the long-term learning effects, which can be achieved by such a serious learning game. Second, we will shed some light on the question, if AR indeed has any influence on the learning outcomes or if it solely impacts visuals and aesthetics of the game.

In order to determine the general learning outcomes of LegionARius, we want to provide the players with several questionnaires. There will be a pre-game-questionnaire asking for some basic data like gender, age, previous experiences with AR, interest in history, prior knowledge about the topic and gaming habits. A post-game-questionnaire is going to incorporate the so-called Game Experience Questionnaire, which "... allows researchers to obtain a reliable and valid indication of participants' subjective experiences associated with digital game-play". Additionally, it contains knowledge-related questions, which could be acquired during the game. In order to determine the long-term learning effects of LegionARius, we strive to question the same group of people after a certain amount of time again and compare the results between the two questioning rounds.

Finally, we will try to answer the question on learning impacts of AR by providing two versions of the game to the players. One group of players will have the chance to play a 2D isometric-top-down version of LegionARius, which will be based on the same game mechanics as the AR-version. This game will be presented as a two-dimensional playing experience, whereas the original title will make use of the possibilities offered by AR.

Prototype Video

LegionARius_Beyond_Limes_WIKI_1.mp4