Extra Large Prims

I was talking to a builder in the Fermi Sandbox who said he thought it would be possible to make a tortured prim of a size of 1000 x 1000 x 1000 meters. Does anyone reading this have experience with very large prims? What is the largest prim that has actually been made (and stays around)?

I believe what he was refering to were "mega prims".
I have heard that one exists that is the size of a sim but I have never seen one (nor needed to) so I can not say for sure.
If you search for mega prims you may get more information.

The biggest prim ever was made through a client-side hack and measured 65535x65535x0.01. It is large enough to cover a total of 65536 sims (a 256x256 grid).

The servers now automatically resize any megaprim greater than 256m in any dimension to a maximum of 256m, so that particular prim no longer exists in its original form. Currently, the biggest prim possible is 256x256x256, which fills an entire sim.

It is not longer possible to create prims of this size; you can only modify (but not resize) the existing full-perms megaprims already in the wild. It has been rumored that future SL updates will allow us to create normal prims up to 20x20x20, but I can't remember if I've ever seen formal confirmation of this.

The Ben & Jerry's sim used to use a 65536x65536 prim for their ocean, which was pretty cool, because it gave you this total cartoon water effect all the way out to the horizon. I don't know what that sim looks like now since the change.

You can not create a new prim anwhere over 10 M in any actual dimension. Torturing can streach them in some ways, but nowhere near that much.

There are "megaprims" or "HDM Prims" that were made some time ago by exploiting a no-longer possible glitch in the system. Existing megaprims can be copied, textured, tortured... but not re-sized. You can get them for free from a number of sources. Using any Megaprim that is 256 M or longer in any domension is highly inadvisable, and can cause serious problems because they overlap into other sims.

For the most part, using any megaprim larger than 100 M in any direction is probably a bad idea. The smaller ones can be used with caution, but don't act quite like normal prims.

I think it's too far into the future for a "you'll definitely get this feature" from LL .

Both larger prims (quoted is "arbitrary size" and a higher prim count are supposidly on the map for future updates though. There are things they want/need to tackle before they can start working on it directly (the first related to Havok4 and encroachment, the second requires work to be done on the sim's object list) so doubtful any time soon.

I was given this prim but I have no intention of using it. I checked the Properties to see who made it for my record book. Any other prim records or building records?

BTW I also have a necklace maker in mind for the maker of the world's smallest prim.