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IDProjectCategoryView StatusDate SubmittedLast Update
0006694opensim[REGION] Physics Enginespublic2013-06-29 11:172014-03-19 15:41
ReporterRichardus Raymaker 
Assigned To 
PlatformOperating SystemOperating System Version
Product Versionmaster (dev code) 
Target VersionFixed in Version 
Summary0006694: llSetKeyframedMotion object is phantom when moveing
DescriptionllSetKeyframedMotion is phantom when its moveing.
Compared to Secondlife where llSetKeyframedMotion is solid and can push avatar.
A phantom object can be problematic with soem type of verhicle designs.
TagsNo tags attached.
Git Revision or version numberf78d2ef-r/22948
Run Mode Grid (1 Region per Sim)
Physics EngineBulletSim
Script Engine
Environment.NET / Windows64
Mono VersionNone
Attached Files

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-  Notes
Richardus Raymaker (reporter)
2013-07-02 04:19
edited on: 2013-07-02 04:26

Ok. done more testing. there's a difference between opensim and secondlife.
if you make a cube the 1x1x1 meter. and add this script.

    touch_start(integer total_number)
        llSetKeyframedMotion([(llDetectedPos(0) - llGetPos()) +
                               <0.0 ,2.0 ,0.0>, <0,0,0 ,1> ,5.0 ],[]);

Then put your avatar in front of the box on the Y axe. then clikc the box.
In secondlife your avatar get pushed in front of the cube. in Opensim the cube is phantom and ignores the avatar. Also it looks like the cube in opensim have more friction so its haveing more trouble to strat moveing compared to secondlife.

Note: corrected a few script mistakes.

Teravus (administrator)
2013-07-02 05:21

I just wanted to confirm this issue. In Havok, there's a kind of movement called keyframe motion whereby physical forces are applied to get objects from waypoint to waypoint. In OpenSimulator currently, physics doesn't really play a part in keyframe motion. Obviously that would have to change if this issue is to be fixed.
mirceakitsune (reporter)
2014-03-18 15:41

I would like to see this get fixed. I'm working on a sim where I plan to add elevators and potentially other objects, which should push avatars and physical prims. This will likely not be possible until then, as well as other things that could be done with this awesome LSL function.
melanie (administrator)
2014-03-18 16:01
edited on: 2014-03-18 16:01

Currently, keyframe motion is nonphysical. If the motion is slow enough, interpenetration management will push the avatar, however, that doesn't extend to things like very fast moving objects or elevators.
Havok gives a great deal of control about collision behavior, allowing an object to move using physics while still being able to penetrate solid prims without ill effects. OpenSim physics do not have this ability, mainly because of the underlying simpler physics module. The SL behavior cannot be duplicated 100% without using the Havok as SL has modified it for their use.
So, the prim moving in keyframe motion is _not_ phantom, it is just _solid_ rather than _physical_. The difference is that a solid prim does not need to traverse intervening space to move from A to B while a physical prim does.

mirceakitsune (reporter)
2014-03-19 15:41

Hmmm... shouldn't this mean that if the elevator has a thick floor and is climbing slowly enough, avatars won't be left behind?

Anyway, only thing I know is that both ODE and especially Bullet are great and complete physics engines. I'd be surprised if there was no solution at all in either of them. But of course I don't know the code, so I cannot say more.

One idea however: What if non-physical & non-phantom objects using llSetKeyframedMotion would be treated by the physics engine as physical objects? Just not affected by gravity and collisions, but with the movement trajectory translated somehow.

- Issue History
Date Modified Username Field Change
2013-06-29 11:17 Richardus Raymaker New Issue
2013-06-29 11:21 Richardus Raymaker Note Added: 0024156
2013-07-02 04:19 Richardus Raymaker Note Added: 0024173
2013-07-02 04:20 Richardus Raymaker Note Edited: 0024173 View Revisions
2013-07-02 04:22 Richardus Raymaker Note Edited: 0024173 View Revisions
2013-07-02 04:26 Richardus Raymaker Note Edited: 0024173 View Revisions
2013-07-02 05:21 Teravus Note Added: 0024174
2013-07-02 05:21 Teravus Status new => confirmed
2013-07-02 10:51 Richardus Raymaker Note Deleted: 0024156
2014-03-18 15:41 mirceakitsune Note Added: 0025467
2014-03-18 16:01 melanie Note Added: 0025468
2014-03-18 16:01 melanie Note Edited: 0025468 View Revisions
2014-03-19 15:41 mirceakitsune Note Added: 0025481

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