Apparently at some time in the recent past, an LL server update re-enabled the ability to create prims with dimensions larger than 10m on a side. There are already lots of new megaprims available, mostly for free (like here on SLExchange:
http://slexchange.com/modules.php?name=Marketplace&file=item&ItemID=685589
). I'm pretty sure most of these prims have been created using LibSL-derived tools.
I don't know if this new-again ability is intentional or not, although I certainly hope it is because megaprims are incredibly useful. Either way, I wanted to be able to create large prims directly in the viewer. My biggest reason for wanting this ability is so that any builds I produce using these prims will then list me as the creator, instead of the creator of the prims that come from megaprim collections. Being able to create them myself also gives me the flexibility to have large prims in whatever size I need, regardless of whether someone thought to create one in advance or not.
This patch implements more of a hack than a feature, for the following reasons:
1. Prims with dimensions greater than 10m can only be created, not resized.
2. As above, I'm not sure if the ability to create these large prims is intentional or not
3. The patch, as it stands, isn't as good or as polished as I'd like for a JIRA submission
4. The creation and handling of large prims in the viewer is quirky
With regards to "quirky", these large prims are subject to a couple of constraints:
a. Prims with dimensions greater than 10m can only be created, they cannot be resized again later
b. Attempts to resize any dimension of a large prim results in all dimensions of the prim being re-clamped to a 10m maximum
The patch itself is actually fairly straightforward. Part of the patch simply enables the Build tools to display and edit scale values larger than 10.0.
Since large prims can only be oversized at the point of their creation, I've replaced the viewer's hard-coded new prim size of <0.5, 0.5, 0.5> with configurable settings. Then I've exposed these settings on the Create tool panel of the Build tools floater.
Put together, these changes make it pretty simple (albeit rather awkward) to create prims of whatever dimensions you'd like.