On Friday 13 February 2004 22:27, Jon S Berndt wrote: > Any chance of modeling wingtip vortices (when CL is high enough above > some threshhold) and rocket engine exhaust? > > :-) > > Jon
I've thought about trying this but I think it could only be really effective in level flight. As soon as you start banking the 'end' of whatever trail you're simulating will rotate (echos of the VRP issues:). For a very short trail this might not be noticable but for longer ones I think it's a bit of a show stopper. It would be possible to include curved trails in the model, and the select anim function could be used to select the appropriate model object, but then you'd need a wide range of trail objects. At first glance, this doesn't seem too bad, but then I think you'd really need several versions of each trail type so that you could switch between them to give the impression that the trail is changing throught time. Hmm... I don't think I've explained that bit very well... Consider an a/c in stable level flight where votices are being generated from the wing-tips. Even though the vortex trail may not change in length or shape, it's appreance will change from frame to frame, so you'd need to switch between several identically shaped and sized objects that are textured slightly differently to give the impression of change. If we could actually modify the model objects themselves then we could 'bend' the trails, and cut down on the number needed. But then we could also do wing flexing too. Before anyone starts thinking seriously about this, it would be very non-trivial to do, at least for the wings, where some objects would need to be 'bent' i.e. the wings and control surfaces, whereas other objects would have to simply translate i.e. wing mounted engine nacelles and U/C. For a simple object, like a vortex trail, bending might be feasible, and combined with scaling (which I think we already have), it might work ok. Another possiblity would be some sort of particle object handling where temporary objects could be generated, left for a while and then culled. We could then 'drop' a stream of these objects behind the a/c that're culled after a certain time. It'd probably need a lot of objects to work though, and it would also push up the object count of course. Both methods would need some carefull texturing. LeeE _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
