Which megaprims are "o.k."

I've heard that Linden Labs is relaxing its policy on not allowing use of megaprims. --True?

I've also heard that there are different types of megaprims (related to who created them). --True?

I've also heard that some types of megaprims are more acceptable than others. --True?

If we can now use megaprims and there are preferred types, which ones should be used?

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Thank you all so much for these great answers and comments. There's a lot to learn in SL.

--Ath

There's no policy preventing you from using megaprims..... you just can't make them. Thousands and thousands are out there, though, so that's not a problem. Yes, there are many packets since many builders took the opportunity to create megamprims during the brief period when it was possible. Hunt around with Search or look on XStreetSL. Use any ones you like....... just be kind to your neighbors. Stay away from parcel/sim boundaries and don't create gawd-awful monstrous eyesores in the sky.

There was talk a while ago about whether specific sizes (I think 128m and larger) should be disallowed, but no rules were made. Certainly anything below 60m in any one dimension is fine with LL.

Be aware that a "cut" megaprim is like any other prim - its bounding box remains the same as the original prim, so it is easy to encroach on neighboring parcels without even knowing it.

You can use the free SALT Hud to quickly locate many many sizes of megaprims. It doesn't have them all, but still can save you a bunch of time searching.
https://www.xstreetsl.com/modules.php?name=Marketplace&file=item&ItemID=712605
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Avoid using the old ones mad by Gene replacement if you can as they were made by prim torture and can get a little funky at times, no offense to Gene BTW, were very handy prims in their day but they have been superseded except for some larger sizes. The size limit is basically what you can fit on rour land, if you got 16 sims then sure rez a 1024x1024 in the middle of them.
The new ones can also have their shape changed, and be cut or hollowed, so you can change a cube into a cylinder etc, no problems.

rule of thumb, no larger than your own parcel (before any cuts/slices), no bigger that 256m if you own a full sim of more (there's some question about how they affect other sims communications with each other if they are larger than that)

recommendations:
1) use the salt hud to find the nearest size you need, it's free on SLX. not only will it save you having to do funky cuts on the megas to get most sizes you need, but it'll also save you hassles when editing because the bounding box won't be ridiculously larger
2) if you MUST use a cut, face the cut side away from the largest amount of traffic (cuts down on on physics processing)
3) do NOT make them physical/vehicles (that's likely to get you AR'd)
4) beware of moving hollowed ones, it'll temporarily treat avs / physics objects inside as being in the middle of a solid prim (they'll all float up/out)
5) do NOT make them your root prim if they will be in items you intend to sell, or they'll show up with a different creator (and you want people to know you created them so that if someone sees it, they can look you up and buy their own)

notes:
as mentioned, some of the created megaprims were made with the old prim-type, which didn't support certain features like hole shape, or bottom tapering, and trying to change the type on these (now) causes them to revert to non-megaprim dimensions I think

There's no difference between Gene's prims and anyone else's. They can have their shape changed, they can be cut and hollowed, just like any other megaprims.

The first megaprims were made long after the new prim types came in, and I've never had a problem changing the type on any megaprims, including Gene's.

could just be a specific set that had prim torture used on it, leaving it in the old prim-type state. I just guessed that the current problem of parameters being reverted on type changes was causing the behavior Tegg saw (as evidenced by the inability to set slice via prim torture in new prim types, possibly in old ones too, I didn't test that, LL shot themselves in the foot on that one.)

Check the minimap when using them to make sure they are not hanging onto someone else's parcel, as megas sometimes have a footprint different than their shape/appearance in world.

Search XStreet-SL for "FREE MEGAPRIM", and use pretty much any of those.

Gene Replacement actually only made about a half a dozen sizes of megaprims. The sets that have 200 or more different sizes of his megaprims are ones made with prim torture - lots of cuts and dimples and other tricks to reduce one if his few sizes to some other usable, smaller size. The few that he made that have a bounding box exactly equal to the prim dimensions, like his 256 M cube, are just fine. But most of the megaprims that have him as Creator have lots of cuts, dimples and other alterations, and like any other tortured prim, they can cause issues because their bounding box and visible size don't match. The worst case with Gene's prims are a few large flat ones that the center of the actual prim is on one corner, and the prim was thinned down using dimples on both flat faces. They hang over way past the edges of the parcel if they are visibly aligned with parcel edges, and neither flat face behaves well for rezzing on.

When a second chance appeared (over a year ago) to make more megaprims, a lot of builders, including myself, pounced on the chance, and we made as many different sizes as we thought might be useful. We only had a few days to work in, but each of us made between 200 and 2000 new megaprims, and virtually all of us made those available to others for free.

Since the "New" megaprims were designed with a wide range of szes, there is virtually no reason to use prim torture to get the size you need. So, for example, a 50 x 50 x 1 M megaprim from my set has a bounding box that is exactly that size, and there is no problem rezzing things on its surface. But if you took my 100 M cube and dimpled it top and bottom to make a 100 x 100 x 0.5 M panel, that prim would have just as many issues as any prim-tortured Gene Replacement Megaprim.

All megaprims can be cut, dimpled, textured, and treated exactly like any other prim. The only thing you can NOT do is alter their actual dimensions on X, Y or Z, because if you do, they get chopped to a max of 10 M in the dimensions that exceed 10 M.

Megaprims are subject to the same bounding box limits as any other prims. So it isn't possible to link the really big ones (over 40 M or so in any dimension) to other prims But you could, for example, link a 20 x 20 x 0.1 Megaprim anywhere that four 10 x 10 x 0.1 prims could have been used to make the same wall.

Be aware that unlinked megaprims will always show the original creator's name. I get a LOT of queries each month from people looking to buy a dance floor, or a tree, or a large statue, that was made from my megaprims. Customers will tend to assume the prim's creator is the maker of the item. And they often click on the largest prims to see who made something. If you make one of your own prims the root, and can link the megaprims to that root in the linkset, this confusion will not happen.

The Lindens evaluated Megaprims after Havok 4 was released. Many builders came up with valid reasons for their continued existance. At first the discussion was to allow tem up to 100 M in size. But others argied a solid enough case for even the very large ones, such as using them as skydomes over isolated private island sims, that the Lindens eventually said the rule would be that they would only act ro remove megaprims on the mainland if they seemed to be causing trouble (for example a cut megaprim was overlapping a neighboring parcel, causing rezzing issues for the neighbor), and that private sim owners vould use them or not, as they choose.

While it is possible on non-SL grids to create Megaprims, those megaprims can not be imported into SL. They will snap to the smaller size limits if you try, even if you use a third-party client that allows importing and exporting prim builds.

I never had a problem changing shape, but I have experienced other problems like them turning phantom at will occassioally and prim drift, I've used a lot of them for wall/floor/roof prims in sizes like 20x20x.5 or 50x50x.5, only the Gene Replacement ones seemed to exhibit this issues so I only use them now for sizes not made in the new type as a last resort. Also I have used a lot of them hollowed and pathcut to make building walls and seen no problems with floating etc inside them since Havok 4 was introduced, for some reason I did have problems with people falling through the floor when they teleported in, but this was fixed by bringing the ground level up as high as possible or replacing them with normal prims in the teleport landing zone. My shopping cetre has prims up to 100m traversing my property for over 12 months with no mutant babies yet recorded

Oh, is that what you all are talking about.

I don't think of those as being different megaprims, they're just a trick, and surely anyone working with prims long enough to actually be building stuff will realize what they are.

I've had that happen with regular prims I've rezzed myself directly from the editor. Sometimes the root prim of a structure will turn phantom, and all you can do to fix it is copy it and throw away the original. I always try and make the root prim of a linkset something that won't matter if it goes phantom any more.

I found that anything over 60M in any direction will make a mess. The biggest factor is Draw Distance


If you use a 60 and stand on one end you will only be able to see 2 of them if your draw distance is 128M - if you use mega prims that are bigger than your (or most people's) draw distance they can only see them if they are closer to the center of that prim.


Just a FYI

I'm not sure how draw distance works when using the huge ones like 1024x1024 or 65kx65k, maybe that's why I've never seen them inworld even with my draw distance normally at 280m, which sort of makes them useless if 90% of the population don't see them.

The ones larger than 256x256 tend to get used as skyboxes for the whole sim. Put a phantom hollow sphere in the center of the sim, and bobs your uncle.

you will only be able to see them if you are within your draw distance to the center of the object.

I found this out a long time ago when I was copying 60's vertically and as I entered a new z they disappeared. So I thought it was a bug and made a few more copies .. later when I flew up.. they re-appeared and I had about 6 of them in one spot.. thats when I realized that the center of the prim is the only thing that matters.

A person with a 96M draw distance standing on the edge of a 256 will probably never see it.