Linksets

From Open Metaverse Wiki

Opensimulator: Documentation: Asset types: Linksets

A linkset is made from two or more prims, meshes and/or sculpts. Linksets are non-hiearchial with one root and all the others parts attached directly to it.

In Second Life the max. number of parts in a linkset is 255. Opensimulator allows for much larger linksets but these can be slow to load and edit so it is usually recommended not to link too many objects.

Numbering and Order

Apart from the root. the numbering of the parts in a linkset is mainly relevant for scripts and not usually relevant otherwise. The root has link number 1, the other parts, the "child prims" are numbered consecutively. An unlinked object has link number 0.

When objects are selected to be linked, the link numbers will be the revesre of the order they were selected, that is the first object selected will get the highest number and the last will become the root. If several objects are selected in one operation (such as when existing linksets are combined) the numbering order is unpredictable except that the root of the last linkset selected becomes the root of the new one.

Linkset order can only be changed by unlinking and relinking.

Two special cases

Sitting avatars

An avatar that sits on an object is technically a part of a linkset but the way it is treated is different in several ways than "regular" linkset parts.

System vegetation

Only mentioned here for the sake of completeness. A system plant is always a linkset but treated a bit different than regular ones.

Known issues

Prim drift

A linkset part have two sets of position and rotation values, global and local (relative to the root). Some editing functions in the viewer and/or server software uses the local values which is added to the root's values when the editing is finalized. This can sometimes cause rounding errors that offsets the affected part. Position values have such a fine scale that the deviation is never noticeable (or at least there are no known incidents of that kind) but it can be a problem for rotation.

Firestorm's part numbering

Firestorm attempts to display pert number in the edit window but those numbers should not be trusted. The root is always correctly numbered but the other parts may not be.

Selection error

Sometimes when you rez a linkset with the edit window open, only the root will be selected at first. To edit the entire linkset you need to deselect and then reselect. It is not clear exactly what causes this. It occurs with one or more specific version(s) of either the viewer or server software but further tests need to be done to narrow it down.