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About doodah2001

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  1. doodah2001

    unreal t3d file problems

    So I was at my local Barnes and Noble today and I was looking at two of the Game Programming Gems books (3 and 4) and I noticed they had a section about T-Junctions. Although this is not straight from the book, this is what I do remember and is somewhat paraphrased as the concept of a T-Junction and why you need to "fix" T-Junctions. For further reading I would look at these books (I think it was in the 3rd book) as it also describes how to fix the T-Junctions. Figure 1: *------------* | | | | | | | | *------------* | | | | | | | | *------------* Figure 2: *------------* | | | | | | | | *---*--------*---* | | | | | | | | *------------* Above are two figures. Figure 1 has two polygons that share the same line. Figure 2 also has two polygons that share the same line. However, the polygons in Figure 1 share the same vertices while the polygons in figure 2 do not. Sometimes when maps are saved, it is assumed that polygons that share the same lines also share the same vertices, however this is obviously not the case (for the same argument above.) This is why you must fix the T-Junctions and also recreate the triangles. I think this may be your problem. Like I said this is just an overview and you can find a lot more information in Game Programming Gems 3. It is in the Graphics section and is called T-Junction Elimination and Retriangulations. A clip from his site: "This gem describes how to detect possible sources of seams in complex 3D scenes and how to modify static geometry so that visible artifacts are avoided. Since T-junction elimination adds vertices to existing polygons (that are not necessarily convex), this article also discuss a method for triangulating arbitrary concave polygons." I hope this helps and good luck. (Edit: ASCII Art Fix, also fixed the GPG #) [Edited by - doodah2001 on May 7, 2005 9:20:48 PM]
  2. doodah2001

    unreal t3d file problems

    Although I haven't personally tried it or looked specifically at the code, I know that Humus over at http://www.humus.ca/ has a t3d loader in his original framework. If you click on the 3d link on the left under the general menu, near the top are links to Framework2, Framework, Libraries, and really old framework, you can download and look at Framework for the t3dloader. Mat
  3. First of all let me say that this is not a "how to crack passwords" thread, so mods please understand that, and if it turns into that then you can shut the thread. I want a true discussion on a problem I was thinking about recently. There will be no mention of how to actually crack windows/unix/linux/any other OS passwords with encryption etc or where they are placed or anything of that nature. This has many other applications than "password cracking" but it was inspired from an article I just read at my internship on computer security and a report that I just submitted. Its been bothering me that there has to be a better way. From the article I will assume that most passwords these days require characters, numbers, and letters together. The average password required now is between 8-10 letters so lets take a password that must be 8 letters with all combinations of letters, numbers, and characters on a standard US keyboard including uppercase letters. You would have a solution space of about 90^8 number of passwords or about 1.14 x 10^15 number of passwords if my math is correct. 90 is the approximate number of available characters on a keyboard (actually I counted 94 but 90 seems nice and round) If you wanted to find every password then you would develop a brute force method that could take up to O(n^8) which is bad. That is with 8 nested for loops running such that the last character cycles through all available characters, then the next to last increments and you repeat cycling through the last character. I figured that would take about 3 weeks. ex. aaaaaaaa aaaaaaab ... aaaaaaba You could also use a dictionary to go through all files and permutations but we're going to assume that our user is a little smarter than that. A second thought, making the assumption you have intelligent users that want hard passwords (we know this doesn't happen) then you could reduce the solution space by leaving out all words that are all characters or all letters (both uppercase and lowercase) or all numbers. That should, if my math is correct, reduce the solution space to about 500 trillion passwords. The problem would be setting up a program that would create this solution space. I personally think that you would have to do more checks for this solution space and you program would end up being slower. ex. aaaaaaa. Assuming that b would be the next letter aaaaaaa> ... aaaaaab. I personally think that reducing the solution space is the best option but it would trade off performance greatly. The number of characters you could get rid of is incredible but the number of checks to get rid of them may be just as bad if not worse than the original. I'm curious as to what ya'll think. Do ya'll have any thoughts on a better implementation? It must be all or nothing. The password must be all right or all wrong. You cannot assume that the password that you are currently testing partially matches the password on the system because the system does not match those types of passwords. mat edit: i'm assuming that there is no limit on the number of attempts for an account and that there is no time to communicate with the host computer. The only time you are dealing with is the actual "cracking" of the passwords. [Edited by - doodah2001 on June 16, 2004 1:06:38 PM]
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