Prim Drift

What exactly is prim drift? What causes it? Is there a way to prevent it? Every now and then, I see that my items have moved a few meters, and move them back, but if I understand it better I won't be so frustrated by it.

Prims moving from the position you put them.

Rounding of position vectors on the server.

Only by placing prims at exact positions that won't get rounded (it's a binary (or was it hex?) thing on the decimals, so you might want to check how it works - I've forgotten).

DISCLAIMER: It's ages since I've poked at SL, my answers may be slightly off or missing in detail.

I had thought that prim drift got fixed a few months back (at least one form of prim drift). Are there any scripts in the object that is drifting?

Prim drift is what happens when a prim you're working with gets bored with what you're doing and tries to escape unobtrusively. You have to keep those prims interested!

That's awfully nice of them. Remember which version so I can go check the notes?

A few *meters*? That's not prim-drift, unless this object is somehow placed at an elevation of about a million meters, or is scripted to do some exotic rotations over thousands of repetitions. A few *millimeters* of "drift" can happen even at 0 elevation in the 0,0 corner (the least "drifty" location) of the sim, due to repeated floating-point rounding. And yes, in the past sim bugs would sometimes cause somewhat larger offsets. But something else must be going on here to offset an object by *meters*. If the objects don't have to move at all, I'd try locking them and seeing if that prevents whatever is causing this.

I don't think it was at all well release noted. Talk to Qarl about the details though, he did the fixing.

One mention in release notes for 1.13.4(59510) March 22, 2007 is that SVC-15 fixed it, but in Jira, some say it has not been fixed.

It's usually people, unless it's that annoying thing where rotations get +/- 0.05 degrees randomly allocated, which makes cracks in multi-part builds.