[week 9 summaries]

The Effect of Latency and Network Limitations on MMORPGs

In this paper, several tests are conducted to help analyze the impact of latency and network limitation on MMORPGs (massive multiplayer online role-playing games).

The basic idea of MMORPGs is introduced with problems addressed to this specific game type. Firstly, to operate such game, the network need to have the capability to host the game enviroment on multi-server architectures. And since this game supports massive amount of players, it is necessary to be able to deal with latency at several game events. Another concern is the way to take care of the huge size f the game world.

A game Everquest2 is chosen as the test subject and three different kind of tests are conducted for analyzing.

The Movement & Combat test is aimed at unveiling the effect of latency on fights. By introducing 0ms, 250ms, 500ms, 750ms, 1250ms, 2000ms, 3000ms and 5000ms latency for each run, the breakpoint can be detected and how bad the latency can effect the fights can be measured. It turns out that though high latency tends to impact more, which is predicted in the hypothesis, the breakpoint is higher than expected. The reason for that is firstly, the movement is rendered locally rather than remotely on network, and secondly, the combat move is queued up such that as soon as the current move is done (which lasts 1sec), the next is instantly executed.

The Group Combat test is designed to fight a monster without healing or level up. By introducing different amount of latency, it is proved that the higher latency impacts more on the fight length. It is possible that the latency may cause decreasing control ability on the monsters and antiproportional relation between remaining resources.

The Movement and Environment test has two parts. The first part only has one player runs with latency. The other runs towards him at same time stamp. The result shows a difference between each players screen, which indicates a dumb-client model. In the second part, both players suffer latency. The result shows the zone server is the one that takes care of movement and placement. The local client only receives player’s local information.

Other aspects like user qualities and MMORPGs on mobile content are also included for analyzing. By conducting tests like this, we can know more about the info structure and network level arrangement. The observation and conclusion can serve as a reference for further game design or other related area.

Alice: Lessons Learned from Building a 3D System For Novices

Alice is a 3D graphics programming environment which is targeting to a wide range of users without necessary 3D graphics, or mathematical, or programming background.

By setting up this goal, there are several aspects that need to be taken care of to make this software more popular and easy to use.

Firstly, since it is not designed for those programming professionals, this software is trying to avoid script as much as possible. They use a very neat and user friendly interface, with clear instruction to follow up. Also, they adjust their vocabulary for keyword and command to make it more acceptable for novices, like for student with math background, he can easily figure out what ‘scale’ mean in that scenario. But for those who haven’t, the word ‘scale’ maybe confusing. Also, Alice abandons the long used XYZ coordinate, and utilizes LOGO-style, object-centric direction. Because for most users, when they try to move the object, they try from their point of view. That is a very intuitive approach. By taking that into consideration, Alice is designed to use Forward/Back, Left/Right, and Up/Down instead of XYZ. In order to let the user know exactly what their operation is, an animation is performed for every command and even whenever it is reasonable. This feature acts like a preview of user’s operation and can help the user adjust easily.

To better assist the user’s design, a long term observation and feedback collection are studied and by summarizing those user experiences, Alice keeps improving to make itself more and more widely accepted and used.

DART: A Toolkit for Rapid Design Exploration of Augmented Reality Experiences

The paper presents us a AR working environment, DART, that can facilitate the collaboration between designers and technologists.

It first starts with the currently existing problems with AR that impede it from being more practical. By analyzing these problems, the author described how DART is designed to overcome them. Specifically, these problems lay in Design and Programming, Enabling Technology and Working in the Real World. By carefully design and implement, DART has advantages over those areas by choosing and unifying its programming language, providing uniformed access to tracking devices and supporting synchronized capture and playback of video and sensor information.

Since Director is a mostly used software for interaction designer, students and research, DART adopt the similar structure as Director to better accommodating the users. DART works with Lingo as its scripts and DART model is similar enough to common Director authoring style. All those are designed to help user get familiar quickly.

Apart from those, DART has its unique features. The define of Physical/Virtual object helps to get a better interactive view; the SketchActor can help the designer test the scene more soon and often; the DARTClock is useful when dealing with synchronize problems, etc.

In all, targeting to practical problems, DART shows its advantages on enabling better collaboration between designers and technologists.

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