From: LeeE <le...@sp...> - 2009-04-17 20:06:29
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On Thursday 16 April 2009, Curtis Olson wrote: > On Tue, Apr 14, 2009 at 12:26 PM, Torsten Dreyer <To...@t3...> wrote: > > > My questions is this ... from a modeling perspective, can > > > that 2nd > > > > aircraft > > > > > be animated with absolute lon/lat/elev and roll/pitch/yaw > > > degrees? Or would we need to compute an X, Y, Z offset in > > > meters for the second aircraft? It would be a pain to figure > > > out the orientation transform relative to the original > > > aircraft ... can the secondary aircraft be animated with > > > absolute angles relative to the world coordinate frame? > > > > > > (For animating the 2nd aircraft, I imagine we'd create some > > > set of custom property names, and I'd drive them externally > > > via some network/file protocol ... maybe creating a custom > > > configuration for the "generic" protocol.) > > > > Don't know if I understand you right, but if you want to create > > arbitrary aircraft with independent position and attitude > > values, you might want to use > > the multiplayer protocol. If you fake the mp-server, you might > > inject any number of aircraft into your scene. > > I was hoping for a reasonably simple solution without needing new > external software development, but the idea of leveraging the > multiplayer protocol is interesting. I notice that with our > existing multiplayer servers, there is at least a many second > delay in positioning the MP aircraft. Is that delay imposed by > the server side, or is there something built into the protocol > that could cause position updates to be delayed before they are > drawn? > > Back to my other idea. It shouldn't be hard to figure out an XYZ > offset of a 2nd piggyback model. But in terms of orientation, > are there animation primitives that would allow me to specify > absolute euler angles for the 2nd model, or would those angle > also have to be computed relative to the primary model > orientation (that's doable I suppose, but my brain has begun to > hurt just at the suggestion of having to do it.) :-) > > Thanks, > > Curt. I can't recall any animation methods that are not relative to the orientation of the aircraft axis. On the other hand though, things like pitch, roll, altitude, lat, lon etc. are absolutes and available in the property tree, so it should be easy enough to derive an equivalent absolute frame of reference. That is, it should be easy enough to use these property tree nodes in your animations while they're atomic values but if it's decided that they should be represented by compound values, and it makes as much sense to use them for lat, lon & alt, or pitch, roll & yaw, as using them anywhere else, you'd have to write some code to parse them first. LeeE |