Can llSetLinkPrimitiveParamsFast move/rotate sitting AVs?

[Dale Innis]

I have a script that lets N people sit on a single prim, with different animations and positions / rotations. It uses llSetLinkPrimitiveParamsFast to position and rotate the sitters, and while that works in SL, it doesn't seem to work in Kitely.

As far as I can tell, the people end up sitting at whatever positions and rotations they would have anyway, without the llSetLinkPrimitiveParamsFast calls in there.

Is that supposed to work?

(Background: we want to make something that two people can sit on, that can then move around as a physical object. If a person is sitting on anything but the root prim, we observe that they move very jerkily. So we figured we'd put them both on the root prim, but then we need to use something other than llSitTarget to position / rotate them...)

[Ilan Tochner]

Hi Dale,

I believe the next version of OpenSim (0.8.0) has several bug fixes for llSetLinkPrimitiveParamsFast which may be relevant for getting this to work. OpenSim 0.8.0 hasn't started the pre-release schedule yet so it will probably take a few more months before that code is included in Kitely.

[Constance Peregrine]

I did the "like" thing for Dale since he did not have any yet and I like to be first and because he works with Karima Hoisan-)) [pls excuse the interruption]

[Dale Innis]

Why, thank you! This is indeed for a world of Karima's; she is the wildly creative idea person, I am just the geeky scripter.

And thanks also, Ilan. Do you know if that release explicitly lists not being able to control AVs with that function as a thing that's being fixed? (I'll try to find the changelist myself, too.) It's always possible that there's some subtle thing I could do differently that'd make it work in Kitely, or even that it's not really a bug at all and I'm just confused somehow...

[Ilan Tochner]

I'm sorry Dale but I haven't read the changelog, I just recall seeing this function mentioned as one of the things that has been worked on.

[Dale Innis]

Ah to answer my own question, looks like it was fixed in late Feb:

http://opensimulator.org/viewgit/?a=com ... 1296c52209

so I'm betting that fix is not in the code running Kitely yet . Thanks again!

[Min Tigerpaw]

Hi Dale,
I studied that issue a while ago when I joined Kitely. What I found out is, that you can move avatars sitting on a linked object but you need to use a different concept than in SL:
While in SL the sitting avi gets the highest linknumber and you can move it by addressing this link-number in Kitely you need to move the prim in the linkset the avi is sitting on.
For that of cause this prim needs to be an invisible prim otherwise it would look weired.
I use this principle im my objects with menu based seating as I sell them in the market or in my regions and it works nicely.

[Dale Innis]

Interesting, thanks! The problem I'd be worried about with that is this "people sitting on non-root prims move very jerkily when a physical object moves via the physics engine" thing. Have you seen that? Or know of a way around it?

[Kayaker Magic]

I have been JUMPING UP AND DOWN ON THE HEADS of the Open Sim developers for years about this issue. The ability to move a seated avatar is important for 1000's of applications. For example the popular AVsitter product in SL DEPENDS on this ability, and furnature in OpenSim has been lacking anything like this. Adjustable seats in vehicles is another use.

The LSL Wiki specifically states that moving the prim an avatar sits on WILL NOT move the avatar. So this is a bug in Open Sim and presumably they will fix it one day and break every script that depends on this "feature".

There is an infamous bug in SL where the difference in the center of gravity between the male and female avatar meshes causes them to sit differently on chairs. Whenever furniture scripters ask LL to add a function to tell them the sex (the center of gravity) of the seated avatar, there is a huge groundswell of objection to this. Apparently people think this function will violate their privacy by reporting the sex of the person on the other side of the keyboard and so they VIOLENTLY OBJECT TO ANY FUNCTION that reports the sex of the avatar. So LL has never fixed or instrumented this center of gravity issue. The only thing scripters can do is provide the ability for seated avatars to adjust their position (for example with the arrow keys) after they sit down. AND THIS HAS BEEN IMPOSSIBLE ON OPEN SIM until (hopefully) version 0.8.0.

There are sims in the OSgrid that are running pre-release 0.8.0 versions, I should go try it out and report back. In my spare time. (There is a good chance I will have some spare time in 2015!)

The "people sitting on non-root prims move very jerkily when a physical object moves via the physics engine" is a different issue. This problem may be fixed by switching to the new BulletSim physics engine, although I think have seen it in non-physical vehicles, especially vehicles with several people sitting on them.