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Back from I3D

I just returned from the I3D conference. It's a very nice conference, and there were a lot of cool papers this time. You should take a look at the complete list at Ke-Sen Huang's homepage.

In particular, I found the following papers interesting:

  • Efficient sparse voxel octrees: This comes with full source code, so be sure to check it out!
  • Stochastic transparency: Very nice use of the MSAA buffer, and pretty nice results. Unfortunately, still a bit slow.
  • Light propagation volumes: An updated version of the SIGGRAPH 2009 presentation, this time with blockers and more explanations. Interesting, as this is the first production-ready GI technique I'm aware of (which runs on current generation hardware ...)
  • FreePipe: A totally insane amount of work. They've implement a full rendering pipeline in CUDA, be sure to keep this on your radar.

Of course, the other papers were also nice, and I liked the overall high quality. I was in all presentations but one, and I have to say that all of them were interesting and had at least one trick worth noting. The really nice thing about I3D is that it's so small that you can really talk with any author and ask him, something which is not true for SIGGRAPH for instance. Asking the authors is highly recommended to get a real understanding ;)

Cannot connect to WPA-PSK2 protected WLAN on Linux ...

The title says it all. I had a machine here with a really old WLAN adapter (Realtek RTL-8185L on a PCMCIA card), and it wouldn't connect to my local WLAN when using WPA-PSK2. I just checked that WLAN was working at all, and yes, it would connect without a pass-phrase, but with a key, it wouldn't work. Each time, the authentication would simply fail due to a wrong password. The Linux was Ubuntu 9.10, but I guess it'll be the same on other ones as well.

One weird issue was that the GNOME applet for entering the network key would refuse my 63 character key, and only let my type in 60 characters. Turns out that the problem is that for WPA-PSK, the key required to authenticate is not your pass-phrase, but generated from the pass-phrase and the SSID, and some drivers don't do this transformation for you, so you have to help out by hand. That's very easy, for instance by using wpa_passphrase. This gives you the PSK, and on entering this one instead of the pass-phrase, everything worked right away. Woho!

Changing XP from retail to OEM ...

Just recently I had to fix a PC with Windows XP. It turned out that the installed version was not "genuine". Du'h, someone helpful re-installed Windows on the machine, but instead of using the original OEM which came with the PC, he installed a retail XP with some key which was obviously invalid. I tried to change the product key to the valid one on the notebook (the one on the Windows sticker with the nice hologram), but the normal way to change keys refused it. Bummer. Called Microsoft, and it turned out that it's an OEM key and the current Windows is not OEM (if you want to check, go to the control panel, system. If your system id is <....>-OEM, you're on OEM)

Ok, so I had to change the XP version from retail to OEM, and then change the key somehow. Turns out that changing the XP version requires a reinstall -- at least that's what I was told by the Windows activation hotline operator. However, there is a different way, by using a tool from Microsoft to change the product key. Guess what, this tool was able to change the product key and the product version at the same time. Voilà , I had finally an OEM windows with a valid key, and could go ahead to install lots of updates as well as other tools that require a valid key like the pretty decent security essentials.

Machine is half-way fixed again; and I still wonder why computer science graduates are supposed to be good at troubleshooting Windows issues ... and I'm always amazed how much crap people tend to install on their machines. Some good advice: If you install some stuff off the web, and you don't use it/know what it is any more, remove  it! And please try to keep your updates on; the machine in question had Firefox 2 and Adobe Reader 8, as well as a 4 year-old antivirus program. That's basically a sure way to become a victim of some exploit.

So much for now, next week we'll take a look at stupid WLAN drivers on Linux and WPA-PSK keys getting refused.

[Update] 2014-10-27: Updated the tool link, thanks to Costi for reporting!

[Update] 2017-09-09: Updated the link to Microsoft Security essentials, thanks to Jeff for reporting!

At the TU Munich

I'm pursuing my Ph.D. since this year at the TU Munich. If you are at the TU Munich, and a reader of this blog, I'd be very happy to get in touch with you, as I have several Master and Bachelor thesis topics to work on :) If you enjoy this blog, you'll be most likely a good candidate.

You can find me at Prof. Westermann's Chair XV (15), Computer Graphics. Chances are pretty high you'll find me in my office. During the next few weeks, I should find some time to upload the theses to the overview page, but feel free to contact me directly if you're interested.


Starting today, I'm moving and won't have internet access at home until at least mid-January. If you want to reach me, try via mail, I should be able to check at least once a day, but answers might take longer. I hope to finish moving by mid-February; with a bit of luck, I'll have most stuff set up again in 2-3 weeks.