Are Mega/Huge prims "dangerous?"

I've seen several thoughts about the "old" big Mega/Huge prims and the use of them.
Some say it's fine to use them, and some say that they'll eventually be "killed" by Linden Lab..

So, what's the truth? Is it still okay to use them, and will they stay in place? Or will I wake up one morning to see parts of my house gone?

If you're on the mainland, megaprims are definitely not allowed and Lindens will remove them when noticed/if causing problems.

One anecdote was someone on help request who complained about a megaprim on the next plot lagging the sim down. A Liason tp'ed over and deleted the offending prim and then onward to return parts of the caller's house because those prims were still lagging things down more than normal.

If you're renting on a private sim, LL won't interfere, but the sim owner might so it's best to check with him/her/them about their policy on megaprims.

Even when non-physical megaprims can - not always - cause weird collision/gravity/lag problems.

All that said, if all you're using is a 20x20 then you're probably fine and if you're using any of the others, just make them phantom.

Thanks a lot, my land is on mainland, so your reply was most helpful.. I think I'll just skip the idea and build with the allowed pieces, no big deal really..

Thanks!

This has been discussed to great lengths many times before, all you needed to do was use "Search" and actually read through the mega prim threads to find the answer, especially the one that isn't even a month old.

The official word from the Lindens is that mega prims are allowed (both private and mainland sim) but they may eradicate all traces of them in the future if they were so inclined.

According to Cory Linden during the Technical Town Hall meeting on December 20th, 2006:


There are a few other links, that I don't remember anymore, where a Linden employee denied the rumor of mega prims being prohibited from use and another one stating mega prims do not cause additional stress to their servers compared to a single regular sized prim.

As long as they're not used to violate other user's private space, general abuse or cross 2 sims, you are allowed to use them, with the blessing from Linden Labs.

As a general rule of thumb, huge prims can be as high as the huge prims are sized but keep the length and width of them within your parcel boundaries. Any huge prim beyond 20m should be set to phantom to prevent strange physics anomalies from occuring.

My 20x20 ones have been in use since January with no real problems , I did have 2 that went phantom after shift slide copying them for some strange reason, but easily fixed by replacing them

Well.. I'm a bit "sensitive", so I don't think I'm up to taking my chances.. I'll stay within limits....

god I Hope they aren't dangerous, I have them all over my sim. (Start eyeing the mega prims suspiciously, hand on her Katana.)

I had one huge monster prim as the sky in our sim for six months. Never had a problem I could attribute to it. But, one day I gave one to a friend who owned two adjoining sims. Upon installing the monster prim sky on one sim, residents of the adjoining sim IMd him of various weirdness going on.

How do you think they got huge ?
They eat smaller unlinked prims at night.
It's true, some years ago there was a bug that made delinked prims unstable and caused them to link themselves with other unstable prims but during that process, their scale vectors were added, making them one bigger prim.
This was a very rare phenomena, it happened only to 2 avatars, Gene Replacement and Charles Fauna.
As you might know, when an avatar seats on a prim, it becomes linked to it.
This is why you cannot find Gene Replacement or Charles Fauna in the People search tab...

Huge prims do not create lag even if physical, on the contrary.
1 huge prim is much easier to deal with than many smaller prims.

Concerning collision and gravity problem, it's because the physic engine doesn't support prims over 10m and doesn't make phantom the parts that should be when you change the shape.
The solution is to do what you're supposed to do with all prims : make sure it doesn't overlap with the neighbor's parcel (no matter how small it looks, you should position it according to the size values displayed in the Build > Object > Size floater).
And if you notice any weird behavior, it's probably Charles or Gene trying to send a message, peace to their souls.

I tried using a mega prim but all of a sudden wierd things were happening when placing items from my inventory to my land.

I deleted the offending mega prims and all worked OK

... I have a few observations.

Megaprims in general don't appear to cause trouble, so long as you're using one of the smaller ones, i.e., 20m on a side, or 40m. Going any bigger than that, though, and you start seeing strange things happening.

Megaprims that cover an entire sim, if stacked up, can actually mess with the gravity calculations and people start floating upwards. This is used as a form of griefing on public sandboxes.

Collisions with megaprims don't always work. When used as a platform or floor, you will sometimes find physical objects just dropping through the prim unhindered. This is because the graphics engine is set to subdivide prims into triangles for rendering and collision checking, but megaprims exceed what the engine is designed to handle. This means that both viewing and collision checking of these giants sometimes fails. I once saw a wild west town set up in the air over a sim where the tumbleweeds kept leaking through the ground plane for the structure and falling to the sim floor below.

Megaprims are usually difficult to texture well. I know this sounds trivial, but you need a very high resolution texture to put on one in order to escape the visual impression of tiling, which generally ruins any scene in which such a prim is used.

Lastly, if a sufficiently large number of physical objects rebound against the megaprim, whether or not the megaprim has its own physics turned on, the collision calculations can quickly overwhelm a server to the point where the sim crashes.

Using the smaller varieties of megaprim usually does not incur any of the above problems. It's only the really big ones that overtax the SL servers and client software.

I'm on Mainland, and I was told otherwise. FROM a linden WHILE they were standing on the huge prim.

We don't really have an official policy regarding megaprims. But here's what you need to know:

1) Use them at your own risk. If they break something, we usually delete them on site and without notice.
2) In the event that you decide to use megaprims, please make them phantom. They cause far fewer problems.

Brenham- nicely put.
Suzhanna- wise.

This is true for any non-phantom prim or non-pantom prim part you are in.

ok, something strange happened over the weekend in my sim.

I tried using a 20 x 20 x .50 mega prim to save some space on my house I'm building. 9(I recall seeing in here that the smaller ones were fairly harmless) About an hour later, I was standing inside the house when I suddenly started floating up until I hit the ceiling.
Remembering this forum post, I tried deleting the 2 20 x 20 prims that I had made and replaced them with 10 x 10's and the problem went away.

At that point I decided that mega prims really were useless all along, and that I'll never use them again.
But yesterday, a full day after I deleted the 2 mega prims, I started floating again and I had to leave my land for the remainder of the day. (this morning everything was fine for the hour I was in SL)

Any idea why I would see that 0 gravity effect for no reason? I did see several people floating up in the sky near me on Friday and Saturday afternoon ...even before I rezzed the mega prims.

Maybe it was just a SIM issue...there were about 42K+ people in SL yesterday.

Sounds like old fashioned griefing. Someone else probably dropped a mega prim on the sim.

I was able to save 70 prims on our skybox by using huge prims (20x20x20) instead of regular prims. Ofcourse they cannot be phantom or we wouldn't be able to stand on it. Hasn't caused any problems.

I've noticed that a hollow huge prim only looks hollow but isn't really until you clip part of it too...

ohh and mega prims has some problems when you path cut them too, seems that mega prims works not with wysiwyg.

update:
I haven't had any problems since last weekend. Musta been an SL thing.

What is LL's official (or unofficial) stance on mega/super prims?
I ask because in the recent article about sculpties, there's a question about using sculpt textures on megaprims, to which LL answered "yes it is possible" and pictured a giant apple.
Is that indicative of LL's support of megaprims (for constructive purposes)?

Just wanted to know where we stand on that... last I heard was when megaprims first came out and were pretty much against the rules to use in any way.

The 'official' stance on Mega/Monster prims in SL, is one of toleration. Apparently, if you already have monster prims in your inventory, you can still 'use' them, but you are not encouraged to do so, or distribute them. The only time that LL take an 'interest' is if they interfere with the sim server, which if misused, they can cause problems. The Jury is still out.

so... as long as you're using what you already have for a constructive purpose (ie building a private low-prim house, making themed objects, etc) it's ok... or rather "we're not going to bother you about it... >_>"

ok... thanks. I was wondering.

back @#10:

Yep, this seems to happen when trying to rez on a mega-prim--much the same as what happens, often, when rezzing inside a hollow cube, for example.

I'm a bit warey of them.

I'm currently building a full sim and some areas could use megaprims. I won't use them because as a developer I know that I develop to a set of parameters.

Therefore I know that if I was writing code for prims, I'd be working on the premise of 10x10x10 prims. Therefore I'll code things with that in mind. So it's perfectly plausible that sometime in the future something will get coded that breaks megaprims.

As a result I won't use them.

Found a more in-depth discussion here:
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