blog.Tiaan.com   Web log of Tiaan Geldenhuys

Every once in a while the SETI@home team updates their list of top candidates for persistent extraterrestrial signals. I thought it might be nice to show these candidates over the Sky in Google Earth (you know, the view where you explore stars and galaxies in outer space), similar to the way I previously illustrated the candidate pixels in an online Google Sky map (see this earlier blog post for the history). As a result, the visualizations of NTPCkr candidates can now also be downloaded as plug-ins for Sky in Google Earth – refer to the list of links at the end of this post. Once downloaded, open the KML file with Google Earth and double-click on any of the candidates listed under “Temporary Places”

Did you know that “Friday the 13th” occurs very frequently? In fact, it is the most common combination of the day-of-the-week and day-of-the-month on our modern-day Gregorian calendar! However, one can say the same for any one of 28 combinations that are equally “most” likely to occur, such as “Sunday the 1st”, “Monday the 2nd”, “Tuesday the 3rd”, “Wednesday the 4th”, and so on. It turns out that all of these common 28 combinations occur in the same month that we find a “Friday the 13th”.

The list below serves as a reference of default hotkeys/keyboard-shortcuts that can be used in Maya 2011 from Autodesk, which is a leading software product used for 3D modeling and animation. Although Maya is a commercial product, a free 30-day trial is available, and the Autodesk Education Community also makes the software available for free to eligible individuals, such as students and faculty members. The shortcuts cover various aspects of the user interface, manipulator tools, full-body inverse-kinematics (FBIK) effectors, selection and editing of vertices, edges, faces, polygons, and more.

The sections below provide a reference of hotkeys/keyboard-shortcuts that can be used in the Unreal Development Kit (UDK), which is the “free for non-commercial use version of Unreal Engine 3” from Unreal Technology. Each section deals with a specific window of the Unreal Editor, such as the main UDK window, the Content Browser, Material Editor, and the editors for Kismet, Matinee, SoundCue and PhAT.

C# code is not inherently slow, and writing code in C++ does not guarantee that your programs will execute fast. For me, these facts were again highlighted by taking part in last month’s Programming Challenge from the C/C++/C# Blog by David Bolton at About.com (which is part of The New York Times Company). The challenge was to calculate a 20x20 Knight’s Tour in the fastest possible time. The final results are out, and my C++ and C# entries ended up in the first and third places, respectively. When comparing my two entries with each other, one can get an idea of how C# and C++ perform when they implement essentially the same logic. Furthermore, one can compare the performance of this C# entry with all the C++ entries and realize that C# code can in fact be very fast.

SimCity Societies is a PC game that allows you to write mods using C# and XML. The game was developed by Tilted Mill and published by EA Games, and an expansion pack is also available, titled SimCity Societies Destinations. However, there is very little information available on the C# application programming interface (API), which makes the coding of a mod somewhat difficult. To enable one to explore the game’s programming environment more easily through an interactive console, I’ve adapted the code from my C# interpreter for Unity 3D to develop a similar plug-in for SimCity Societies (SCS for short), and this resulting rework also works with SCS Destinations. The interpreter mod/plugin opens a separate console window for input and output interactions. Without the interpreter console, you may often need to restart the game after making small changes to scripts in an attempt to figure out what an API member actually does, which tends to be a slow and tedious process; but with the console, the experimentation process becomes instantaneous. Furthermore, the interpreter can serve as an interactive debug tool for your actual mods, or you can even use it as a cheat console to do things such as adding Simoleons to your treasury with the “CS_Player.ModifyCurrentMoney” method (see example further down). As with the earlier C# interpreter, the rework is released as open-source software under the MIT License and is available as a free download. The rest of this article describes how to install and use the software.

When we look at objects in the sky, out there in the solar system, galaxy and universe, we often see a pattern where numerous smaller or lighter items are scattered in a disk-shaped formation and are orbiting around something larger or heavier. For example, there are planetary rings, such as the prominent ones found around Saturn’s equator, which consist of things like dust, ice, rocks and moonlets. Then there is our Solar System: the Sun with the planets orbiting within a relatively flat disk around it — and the planets are thought to have formed from a protoplanetary disk. Also, at a larger scale we have, for example, the spiral galaxy with a central bulge and a rotating disk of stars around it (defining its galactic plane). So, rotating disks of celestial objects are quite common and repeated at every size scale; but how do they get to have that specific shape? Scientific explanations go along the lines of: the process starts with a cold cloud of gas and dust, the cloud collapses under gravity, and “conservation of angular momentum causes any small net rotation of the cloud to increase, forcing the material into a rotating disk”. But what does that really mean? Even astronomers say: “it’s so hard to explain in simple words”.

CSI is a simple C# interpreter that was originally developed by Steve Donovan and it works similar to the more recently developed C# interactive shell of Mono, named CsharpRepl. For a while I’ve been making some improvements to CSI and recently developed a plug-in/script version of it for Unity, the 3D game-development environment, which is compatible with the older version of Mono that Unity makes use of. The plugin allows one to execute C# code in an interactive console while the game is running, which can assist with debugging and be used to explore the runtime environment. The software is known to work on Unity 2.6.1 in both the Editor application and Standalone Player on Windows, but it might also work on the Mac OS. It also works on Unity 3.0.0 and 3.1.0 for PC (as of CSI version 0.8.24.3). The CSI plug-in is available as a free download and released as open-source software under the MIT License.

It is technically possible to run a website on Mono (the open-source .NET development framework) using the Shared Hosting servers at DreamHost. The technique makes use of the pre-installed FastCGI module that is available on DreamHost’s Apache web servers, which is then configured to dynamically start the Mono FastCGI Backend. Just like for any other dynamic FastCGI server (such as for PHP FastCGI), the FastCGI module of Apache would monitor and manage the Mono FastCGI persistent processes and start/stop them as needed, in line with DreamHost’s configured FastCGI policy. The Mono FastCGI Backend is distributed as part of Mono’s XSP package, which needs to be built and installed along with all the other supporting Mono binaries. This procedure is detailed below, and an example Apache configuration is also provided for a basic Mono web-application that contains some standard ASP.NET pages (.aspx files) and a Web Service (.asmx file). With that in place, you can explore the rest of what Mono has to offer on a shared web server.

The Near-Time Persistency Checker (NTPCkr) recently went online, which allows SETI@home to publish an up-to-date list of their best candidates for persistent extraterrestrial signals. The dynamic NTPCkr top-10 list also contains a “skyplot” link for each candidate, which shows a picture of the candidate’s location on the sky using a Google Sky Map with a custom crosshair marker indicating the center of the pixel region where the signals were detected. As pointed out by Jon Golding (in this forum comment), the NTPCkr should “perhaps show the region of interest on a skymap (i.e., not crosshairs)” to illustrate this more clearly. Joe Segur shared this sentiment, stating that “plotting would ideally show the boundaries of the pixels”. The equations needed for calculating these SETI@home pixel boundaries are given below, along with an example JavaScript implementation, making such an enhancement straightforward.