I am also interested in physics for vehicles mainly for creating working yacht and for making my free moving scripted animals to work in a smooth way. If there is a way I can contribute I will try to do so.
6 jun 2012 kl. 01:46 skrev Mike Higgins: > I was talking to Justin Clark-Casey at the OpenSim developers meeting > this morning, and he suggested that the mailing lists would be the easiest > way to have a conversation about vehicle physics on OpenSim. Justin you > there? Is this where you meant? Anyone else want to talk about vehicle > scripting in OpenSim? > > I am in the process of testing the OpenSim vehicle scripting calls and > trying to find out what works and what can be worked around. I am submitting > mantis reports when I think I see a true bug, issue numbers 0006039 and > 0006040 for starters. Instead of submitting 1000 line vehicle scripts that do > not work, I am writing small 10-line scripts that demonstrate a particular > problem. > > Issue 0006040 is particularly interesting because if my hypothesis is > correct, the linear motor direction is being actively projected onto the > global XY plane. I cannot get an airplane to glide up, or a balloon to rise > using the linear motor. (Hover height works with balloons, but not the linear > motor even with hover height disabled). The interesting thing about this is > that my hypothesis suggests that there is extra code doing this projection > onto the XY plane. I checked the vehicle flags and there isn't one that > should force this extra projection into the calculations. Vehicle type > balloon is supposed to have all the flags removed, but just to be sure I used > the remove call to clear them all. The linear motor still cannot go up. Can > someone familiar with the code look at the linear motor and tell me why this > is happening and if there is a way to disable it? (I tried turning flags > like VEHICLE_FLAG_NO_DEFLECTION_UP on to see if this flag was inverted, and > if it applied to the motor instead of deflection, but no luck). > > The fun thing is that I can write one kind of vehicle that works well -- > assuming this bug is there. I built a vehicle that has the linear motor set > to <0,0,20>, pointing straight up. When the vehicle is perfectly horizontal, > the projection of this motor onto XY is <0,0,0> and the vehicle does nothing. > But then when you tilt the vehicle in any direction, the projection of the > linear motor on XY becomes non-zero and causes it to start moving in the > direction of tilt. This feels a lot like an RL helicopter, so I used the > control keys to pitch down/up to move forward/backwards, added yaw left and > right, and used page-up/down to increase/decrease the hover height. I put it > in a hacked together helicopter build and it is a lot of fun! > > I'm looking for work-arounds for the current vehicle routine behaviors. > One work-around for an airplane is to turn on hover height, check the > airplane speed and pitch once a second in timer(), calculate what altitude > the plane should get to in the next second, and set hover height to that > altitude. The things we do to get stuff working! > > > > _______________________________________________ > Opensim-dev mailing list > [email protected] > https://lists.berlios.de/mailman/listinfo/opensim-dev
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