Why are there prim limits on coalesced objects?
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Why are there prim limits on coalesced objects?
To answer this question, a brief overview of object rezzing mechanics is necessary. When an object begins rezzing (appearing inworld), the simulator stops simulating its Region until the object rez is complete. For most objects, this simulator freeze is usually not noticeable. However, the more prims in a complex, coalesced object, the longer the rez time. As of Second Life Server 1.25, there has been a rez timeout of 15 seconds. If the complete object can't be rezzed before that timeout occurs, no portion of the object is rezzed and the rez fails. This timeout has been increased to 30 seconds in Server 1.26 for a landowner rezzing something on their own land.
The rez timeout creates a problem when Residents take complex coalesced objects into their inventory that they then can't rez before the timeout occurs. In order to be able to rez these objects, Residents need to create a Support ticket asking for the object to be broken into a set of smaller objects. The prim limit on coalesced objects is meant to prevent attempts to take objects into a Resident's inventory that will be too complex to rez before the rez timeout.
Why does the simulator stop simulating its Region to rez an object?
The simulator will stop simulating its Region to rez an object so that the physics engine doesn't act on any of the rezzed prims in that object before all the prims in the object have finished rezzing. For example, you wouldn't want the seat in a boat that's scripted to travel between islands to begin moving before the rest of the boat has rezzed. Nor would you want a game ball to rez before the stadium floor, since it would fall to the ground below.