Link, when used in reference to building/scripting, means to link two or more prims together to form one cohesive object. There are various script functions that have to do with linked objects. A linked object can also be referred to as a group but can be confusing.
A link is also another name for a URL.
To link prims, first right-click a prim and select "Edit" (the edit window should appear), then hold down the "Shift" key and select another prim. With the two prims selected, either go to the tools menu and select "Link" or use the keyboard shortcut "Ctrl-L". The two prims will now be "linked" together with the "root" or "parent" prim being the last prim selected before linking (it will be highlighted in yellow while the "child" prims will be in blue). To select a group of prims quickly, left-click while in "edit mode" and dragging the mouse; the first prim highlighted will then be the parent prim.
To unlink a group of prims, select the "link set" (while in edit mode) and either select "Unlink" from the tools menu or use the keyboard shortcut "Ctrl-Shift-L". If a set is unlined, then linked again without deselecting the set, the parent prim will be remembered.
- Unlinking a physical object tends to cause the prim pieces to "explode" (due to collision calcuations) or get stuck (which can cause lag or a sim crash) when the set is deselected.
- To take a group of objects or prims to inventory without linking, shift-select them and then "Take" them.