Thanks for the help, Jason! 2008/7/10 Jason & Debbie Wandel <[EMAIL PROTECTED]>: > The technical term is a "toroid". If you take a piece of flat paper and bend > it around so top and bottom edges meet, and then wrap the cylinder around so > the ends meet, you get a donut shape - which is a toroid (for those > interested in trivia, my understanding is that the toroid is the only 3-D > shape in which cartesian geometry holds true on its surface, e.g. the sum of > the internal angles of a triangle adding to 180deg. If you do the same on > the surface of a sphere, you get 270deg instead - try it with a globe of the > earth next time! This is why it is hard to imagine a planar circle wrapped > down to a sphere).
I implemented it in my client in a way that it looks for the minimal X and minimal Y distances (looking for all kinds of wrap-around), then calculates the distance from these values. This seems to produce good data, and at first glance also seems to be consistent with the toroid shape. > > Personally, since RFTS has a limited number of stars and fleets can't change > directions, I'd keep some kind of lookup table and just specify distances > between each star. It would save you a lot of calculations! Hm, it actually sounds like a good idea; I'll consider it! > > Normalised simply means that everything is referenced to a particular > arbitrary value. So, an example: the average distance between the earth and > the sun is 148 800 000 km (93 000 000 miles for you Americans). In solar > system astronomy, this is normalised to 1 AU (astronomical unit). Venus' > orbit is roughly half way in from the earth's orbit, so it is listed as > roughly 0.5 AU. Mars at roughly twice the distance is listed as ~2 AU. > > The idea is to make the math easy by eliminating all those pesky 0's - or to > turn floating point math into integer math by having integer multiples of a > floating point value. Since all the normalised values are referenced back to > the same arbitrary value, you effectively divide every value by that > arbitrary value and it disappears from your equations altogether... Cool, I was suspecting that in this context, it actually meant defining the X and Y boundaries by the outer-most star-systems, but I wasn't entirely sure. (Well, there is still a possibility that there is some fixed "buffer zone" along the edges). > > -J > > _______________________________________________ > tp-devel mailing list > [email protected] > http://www.thousandparsec.net/tp/mailman.php/listinfo/tp-devel > > Cheers, -- Victor. Truth is greater than ten goats (Nigerian proverb). _______________________________________________ tp-devel mailing list [email protected] http://www.thousandparsec.net/tp/mailman.php/listinfo/tp-devel
