Animating prims within a linkset.

[Adamthebest]

Hi, I'm trying to make a sliding door script but cannot figure out for the life of me how to smoothly slide the door within a linkset. Was looking for a solution similar to llSetKeyframedMotion, however that can only be applied to the root prim. Could anyone give me any pointers?

 

Thanks.

[ChinRey]

Usually sliding doors use llSetPos().

You can probably get smoother movement with llSetLinkPrimitiveParamsFast() though.

[Adamthebest]

Hi, thanks for the suggestion. Do you have any suggestions on how I could achieve a smooth movement with SetLinkPrimitiveParamsFast? I know you can set position using it, but reading the wiki, I can't see any keyframing options.

[Nova Convair]

You need to script it. Make a loop and move it with llSetLinkPrimitiveParamsFast in small steps. 15 moves per second are sufficient - with more you are not gonna see a difference. llSetPos is too slow for that movement.

You can set the delays with llSleep or use the timer. With llSleep the script will be unresponsive during the movement but for a door script that is tolerable.

[Adamthebest]

Thank you for the suggestion! I'll give that a try now.

[Rolig Loon]

Try this for a pointer >>> https://community.secondlife.com/t5/LSL-Library/Linkable-Multiprim-Sliding-Door/m-p/722649

Nowadays, I would clean it up and make it simpler by using PRIM_POS_LOCAL and PRIM_ROT_LOCAL, but the logic would be the same as when I wrote it 5 years ago.

[Qie Niangao]

Nexii Malthus stocked the wiki with a handy library of Interpolation functions, including cosine interpolation, a cheap and easy solution for when "smooth movement" should include an accelerating start and slowing to a stop. 

(I stumbled on that page recently when checking if there's a "quaternion-native" way to interpolate rotations, without converting to and from angles. Answer: Not that I found.)

[Rolig Loon]

THAT is a lovely discovery, Qie!  Thanks for pointing it out. 

[Nova Convair]

Oh, nice library Qie.

I have been using slerp for rotations ( Slerp ) and simple linear interpolation for positions ( (pos2-pos1)/no_of_steps ).

The next time I move something I'll see what I can do with that library.