0006039: VEHICLE_ANGULAR_MOTOR_DIRECTION does not rotate around the vehicle local axes

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0006039

opensim

[REGION] Physics Engines

public

2012-06-01 23:10

2012-06-07 03:25

Reporter

Kayaker Magic

Assigned To

Priority

normal

Severity

minor

Reproducibility

always

Status

confirmed

Resolution

open

Platform

OpenSim 0.7.1.1 Release (Unix)

OS Version

Product Version

Target Version

Fixed in Version

Summary

0006039: VEHICLE_ANGULAR_MOTOR_DIRECTION does not rotate around the vehicle local axes

Description

    The LL Wiki (http://wiki.secondlife.com/wiki/VEHICLE_ANGULAR_MOTOR_DIRECTION [^]) is ambiguous about what axes the angular motor rotates around. However the Linden Vehicle Tutorial (http://wiki.secondlife.com/wiki/Linden_Vehicle_Tutorial [^]) does mention in passing that the angular motor rotates the vehicle around its local axes.

    HOWEVER, in OpenSim, the angular motor apparently always rotates around the global region axis. This tilts a vehicle at all sorts of unexpected angles depending on which direction it is facing.

    A workaround is to always multiply the vector sent to to the angular motor by llGetRot(). I suspect this is not quite right, because for long turns the local axes will be continuously changing. For short turns this makes the vehicle behave well enough.

Steps To Reproduce

Make a prim that is longer in the local X direction (so you can tell if it turns it's nose down). Make sure the prim is high enough off the ground to rotate.
Place the following small script in the prim. It SHOULD pitch it's nose down, but instead it rolls sideways.

Additional Information

// angular motor test
// Kayaker Magic
// Place this script in a prim that is far enough above ground to rotate freely.
// preferably something long in the local X direction so you can tell
// if it correctly dips it's nose down.
// This should make the prim rotate around it's local Y axis, but
// you will see it rotates around the global Y axis
default
{
    state_entry()
    {
        llSetStatus(STATUS_PHYSICS, FALSE); //disable physics on reset
        llSetRot(llEuler2Rot(<0,0,PI_BY_TWO>)); //rotate local axis
        llSetVehicleType(VEHICLE_TYPE_BALLOON); //simple vehicle, nothing fancy
        llSetVehicleFloatParam( VEHICLE_HOVER_TIMESCALE, 10000 ); //disable hover height
        llSetStatus(STATUS_PHYSICS,TRUE); //turn physics on when ready
        llSetVehicleVectorParam(VEHICLE_ANGULAR_MOTOR_DIRECTION, <0,4,0>); //pitch nose down
                //the vehicle should pitch around the local Y axis, but rolls around the global Y
    }
}

Issue History
Date Modified	Username	Field	Change
2012-06-01 23:10	Kayaker Magic	New Issue
2012-06-07 03:25	justincc	Assigned To	=> justincc
2012-06-07 03:25	justincc	Status	new => confirmed
2012-06-07 03:25	justincc	Assigned To	justincc =>

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