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<DIV>I might add that in OpenSim vehicles features such as total instance wind
control and mega-regions afford an environment superior to SL. </DIV>
<DIV>These and others, not available in SL, dictate a fresh approach rather than
importing ancient scripts.</DIV>
<DIV> </DIV>
<DIV>:)</DIV>
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<DIV style="font-color: black"><B>From:</B> <A title=mike@kayaker.net
href="mailto:mike@kayaker.net">Mike Higgins</A> </DIV>
<DIV><B>Sent:</B> Tuesday, June 05, 2012 4:46 PM</DIV>
<DIV><B>To:</B> <A title=opensim-dev@lists.berlios.de
href="mailto:opensim-dev@lists.berlios.de">opensim-dev@lists.berlios.de</A>
</DIV>
<DIV><B>Subject:</B> [Opensim-dev] Questions about Vehicle scripting
calls</DIV></DIV></DIV>
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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?<BR><BR> 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 <SPAN class=small><A
title="[new] VEHICLE_ANGULAR_MOTOR_DIRECTION does not rotate
around the vehicle local axes"
href="http://opensimulator.org/mantis/view.php?id=6039">0006039</A> and
</SPAN><SPAN class=small><A
title="[new] Vehicle linear motor is projected onto the region
global XY plane"
href="http://opensimulator.org/mantis/view.php?id=6040">0006040</A> 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.
<BR><BR> Issue </SPAN><SPAN class=small><A
title="[new] Vehicle linear motor is projected onto the region
global XY plane"
href="http://opensimulator.org/mantis/view.php?id=6040">0006040</A> 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).<BR><BR> 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!<BR><BR> 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!<BR><BR><BR><BR></SPAN>
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