Positioning a prim with llSetPos()

[Asimos]

I have attached a prim on pelvis. Prim Local position is <0,0,0> (so I do not have to worry about small deviations from the center)

I want to reach a target at Global Position <123.5, 130.0, 20.0>.

My avatar is at Global Position <120.0, 125.0, 21.0>.

My basic math tell me that the following should approximately place the prim on the center of the target. My avatar is facing the target (so I do not have to worry about rotations at this point in time). Yet is does not work. Any ideas why?

...

vector target = <123.5, 130.0, 26.0>;
vector avatar = <120.0, 120.0, 26.0>;
llSetPos(target - avatar);

...

[Rolig Loon]

Well, for one thing, you are too far away.  You can't move anything with llSetPos more than 10 m.

Beyond that, when you use llSetPos in an attachment, the position vector is a local vector, relative to the attachment point, not relative to the avatar's global position.  See http://wiki.secondlife.com/wiki/LlSetPos#Coordinate_Frame .  The same is true for rotations and llSetRot.  See http://wiki.secondlife.com/wiki/Rotation#Single_or_Root_Prims_vs_Linked_Prims_vs_Attachments .

[Asimos]

Actually I am NOT that far. With those coordinates, I shouldn't be more than 11m, and I chose those coordinates on purpose (Delta X=3.5, Delta Y=10m, Delta Z=0) to stimulate a more in-depth disuction with the forum on llSetPos and its limits. Also, I chose for simplicity the prim be positioned on the center of the avatar with local coordinates <0,0,0>.

But let me change the coordinates if that helps to refocus the discussion on the real issue . With the following coordinates the distance is well below 10m, yet it does not work:

vector target = <123.5, 130.0, 26.0>;
vector avatar = <120.0, 129.0, 26.0>;
llSetPos(target - avatar);

A fast diagram will help you understand that, for approximate positioning, what I'm doing is good enough (please keep it simple, and as I said, localvector=<0,0,0>. Once I understand why that does not work, then adding the local vector is trivial).

 

[arton Rotaru]

Looks like the root of an attachment can't be further away than 3.5 meters from the attach point. Just try to drag it manually, and it won't go any further either.