# Sitting on Rotating Linked Prims (llTargetOmega)

Please take a moment to consider if this thread is worth bumping.

## Recommended Posts

Consider 2 Prims, A and B, a few meters apart.  These are cubes so that their rotation is easily seen.

Link them, making Prim B the Root.

Add a Poseball Sit script to Prim A so that when sat upon, the avatar faces Prim B.

Put a Rotation Script (llTargetOmega) in Prim B (root) with rotation about the Z-axis with clockwise rotation (speed = R).

The result is that the Avatar orbits the root prim in the horizontal plane, and the avatar always faces Prim B (root).

NOW...

Unsit the Avatar.

Add a Rotation Script to Prim A (the seat prim) with a counterclockwise rotation (speed = NEGATIVE R).

Observe Prim A (seat) orbitting Prim B (root), and since Prim A is rotating in reverse from Prim B and at the same rate (but negative), Prim A (seat) always faces the same way, i.e. it's East face always faces East, or, it revolves around Prim B but does not rotate relative to the region coordinates.

OK, that is good, and it what is expected, but NOW...

Sit on Prim A and the Avatar does NOT always face East as I want it to.  It continues to face Prim B (root) and rotates based on Prim B (root) rotation, not the combined net rotations as does Prim A (seat) when vacant.

So.. I want my avatar to ride this merry-go-round and always face East.  Any advice?

Thanks, Dash

##### Share on other sites

One answer is on the near horizon. Maestro Linden announced on June 21 that

"The 'fix' is to have a new constant for the ll?et*PrimitiveParams() functions, called PRIM_OMEGA. It follows the same basic syntax as llTargetOmega(), so you can use it by e.g. calling

llSetPrimitiveParams([PRIM_OMEGA, vector axis, float spinrate, float gain]); "

﻿It was released on Blue Steel servers the next day and, barring disasters, should be available elsewhere soon.

##### Share on other sites

avatars are child prims for the purposes of rotation... the means they follow the roots rotation.

##### Share on other sites

It will be good to know ahead of time that PRIM_OMEGA does not work on avatars. All we get is an error message, "PRIM_OMEGA disallowed on agent﻿" There could still be opportunities to play with seats.