2010/4/9 Stuart Buchanan <stuar...@gmail.com>: > Frederic Bouvier wrote: >> Glad to see the effect is used. I noticed the bump is reverted on one axis. >> In a previous thread, I wrote : >> >>> I use the GIMP normal map plug-in to create my normal maps. Here are two >>> example. A bump : >>> http://frbouvi.free.fr/flightsim/gimp-normalmap-bump.png >>> >>> A hole : >>> http://frbouvi.free.fr/flightsim/gimp-normalmap-hole.png >>> >>> They are created from the same "height field" image. Reds should point to >>> the bottom right and greens should points to the top left. >>> >>> More precisely: >>> #FF7F7F points to the right >>> #7FFF7F points to the top >>> #007F7F points to the left >>> #7F007F points to the bottom >>> >>> These are the only two realistic combinations. Remember that for OpenGL >>> the origin of the image is the bottom left when the origin of an image >>> is the top left, so that's why an axis should be reverted. >> >> Looking closely at the wing map : >> http://frbouvi.free.fr/flightsim/gimp-normalmap-c172.png >> >> It appears that reds are pointing to the top right and greens to the bottom >> left. You may need to check the 'Invert Y' box in order to get them right. > > Thanks for the help. I've updated the normal maps, and included this > information in the wiki article. >
This is some nice artistic/graphical work indeed, however, I am afraid this is not very realistic. If you want Cessna aerodynamicists to die from an heart attack, just show them this picture ^_^ In real life, and on most modern aircrafts, you do not have such protruding rivets unless you want your fuel consumption to go through the roof. Countersunk head rivets are used nowadays and their number and position are the result of a tough battle between the design office (who want a strong/cheap/light structure) and the aerodynamics office (who want very smooth/expensive air washed surfaces) ^_^ The result of these hard negotiations is that rivets *must have* a countersunk head (it is a minimum to enter a round of negotiation ^_^), there must be as few as possible of them, the gap between the rivet head and the countersunk hole should often be filled by a sealant (or at least by paint ^_^ both of them cracking in service anyway ^_^) and rivets with protruding heads are not an option (don't even think about them, unless you want to be crucified on the public place ^_^). The result, unfortunately, is not very spectacular as can be seen on the picture that Martin Spott sent a few days ago (http://foxtrot.mgras.net/bitmap/FGFS/DEEQA-Oelklappe.jpg) but it significantly improves your aircraft performance (and make the aerodynamicists happy - which is priceless). Cheers, Bertrand. P.S. No offence is meant to the aerodynamicists. They are very smart guys (you have to when you are involved in CFD) and most of them are really cool guys. Furthermore they are the greenest dept of an aircraft manufacturer since all their work is dedicated to the reduction of the fuel consumption ^_^ ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
