Second Life Forums Archive

Dalea Kojima

Registered User

Join date: 31 Mar 2004

Posts: 27

05-11-2005 11:52

Hi!
I was wondering why prims can only be 10 x 10 meters big?
Is there a technological reason?
Would one 20x20 cube have a bigger performance impact than 4 10x10 cubes?

Thanks,

Dalea

Aliasi Stonebender

Return of Catbread

Join date: 30 Jan 2005

Posts: 1,858

05-11-2005 11:59

It primarily has to do, as I understand it, with moving prims across sim boundries. You need to have a certain amount of overlap in data sent to a client, and larger prims require a larger overlap. Allow them too large, and you're loading every sim for three sims around you!

Osgeld Barmy

Registered User

Join date: 22 Mar 2005

Posts: 3,336

05-22-2005 21:33

just to bicker....

yea i can see your information being correct... but wouldnt the sims have less data if there were 4x less prims?

yes you have signs and ect, but you know biuldings, which are the things that take forever to rez and i get stuck inside a wall, most of the times around telehubs

Olmy Seraph

Valued Member

Join date: 1 Nov 2004

Posts: 502

05-22-2005 22:14

From what I've heard, it has to do with the physics engine. A sim has to know about prims that are located on neighboring sims, but overlap onto its space. This is so that avs and other physical objects moving on a sim interact correctly with those overlapping prims. The size of the overlap region is tied to the max size of prims, so if you make that bigger there is a bigger overlap, and that is a performance hit.

_____________________

Some people are like Slinkies... not really good for anything, but they sure bring a smile to your face when you push them down the stairs.

Jeffrey Gomez

Cubed™

Join date: 11 Jun 2004

Posts: 3,522

05-24-2005 20:16

I have seen how older prims function (edit: prior to the fix for the bug). The owner of Nexus Prime had a few rezzed in-world, presumptively from before my time in SL.

The physics engine didn't like it. The collision data was flawed, and I'd bet getting it to cross sim borders (as mentioned) would be a calculatory nightmare.

Compounding the problem is the fact extremely large objects create a spacial issue. I wouldn't want someone dropping a 200m-large frying pan on me in the sandboxen, for example. It really strikes me as a more managable, intuitive limitation.

_____________________

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Eggy Lippmann

Wiktator

Join date: 1 May 2003

Posts: 7,939

05-25-2005 07:08

There wasn't a time before the cap, Jeff... there was just a short time during which a bug existed with linking and llSetScale

The bug was that if you had a tiny prim and a huge prim linked, and you called llSetScale on the tiny one, it would also resize the large one, making it go outside the 10m limit.

_____________________

Help us document Second Life history at http://slhistory.org!

Jeffrey Gomez

Cubed™

Join date: 11 Jun 2004

Posts: 3,522

05-25-2005 20:54

Point taken.

Makes me wish I'd been savvy/around at the time.

_____________________

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Kyrah Abattoir

cruelty delight

Join date: 4 Jun 2004

Posts: 2,786

05-25-2005 21:00

i experienced some ways to create links that are bigger than the value allowed (i did up to 120 meters) seems the physic really hate it as the linked prims whare almost like phantoms

_____________________

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apez http://tinyurl.com/yfm9d5b
metalife http://tinyurl.com/yzm3yvw
metaverse exchange http://tinyurl.com/yzh7j4a
slapt http://tinyurl.com/yfqah9u

Welcome to the Second Life Forums Archive

Why 10x10?

Why 10x10?
Dalea Kojima Registered User Join date: 31 Mar 2004 Posts: 27	05-11-2005 11:52 Hi! I was wondering why prims can only be 10 x 10 meters big? Is there a technological reason? Would one 20x20 cube have a bigger performance impact than 4 10x10 cubes? Thanks, Dalea
Aliasi Stonebender Return of Catbread Join date: 30 Jan 2005 Posts: 1,858	05-11-2005 11:59 It primarily has to do, as I understand it, with moving prims across sim boundries. You need to have a certain amount of overlap in data sent to a client, and larger prims require a larger overlap. Allow them too large, and you're loading every sim for three sims around you!
Osgeld Barmy Registered User Join date: 22 Mar 2005 Posts: 3,336	05-22-2005 21:33 just to bicker.... yea i can see your information being correct... but wouldnt the sims have less data if there were 4x less prims? yes you have signs and ect, but you know biuldings, which are the things that take forever to rez and i get stuck inside a wall, most of the times around telehubs
Olmy Seraph Valued Member Join date: 1 Nov 2004 Posts: 502	05-22-2005 22:14 From what I've heard, it has to do with the physics engine. A sim has to know about prims that are located on neighboring sims, but overlap onto its space. This is so that avs and other physical objects moving on a sim interact correctly with those overlapping prims. The size of the overlap region is tied to the max size of prims, so if you make that bigger there is a bigger overlap, and that is a performance hit. _____________________ Some people are like Slinkies... not really good for anything, but they sure bring a smile to your face when you push them down the stairs.
Jeffrey Gomez Cubed™ Join date: 11 Jun 2004 Posts: 3,522	05-24-2005 20:16 I have seen how older prims function (edit: prior to the fix for the bug). The owner of Nexus Prime had a few rezzed in-world, presumptively from before my time in SL. The physics engine didn't like it. The collision data was flawed, and I'd bet getting it to cross sim borders (as mentioned) would be a calculatory nightmare. Compounding the problem is the fact extremely large objects create a spacial issue. I wouldn't want someone dropping a 200m-large frying pan on me in the sandboxen, for example. It really strikes me as a more managable, intuitive limitation. _____________________ ---
Eggy Lippmann Wiktator Join date: 1 May 2003 Posts: 7,939	05-25-2005 07:08 There wasn't a time before the cap, Jeff... there was just a short time during which a bug existed with linking and llSetScale The bug was that if you had a tiny prim and a huge prim linked, and you called llSetScale on the tiny one, it would also resize the large one, making it go outside the 10m limit. _____________________ Help us document Second Life history at http://slhistory.org!
Jeffrey Gomez Cubed™ Join date: 11 Jun 2004 Posts: 3,522	05-25-2005 20:54 Point taken. Makes me wish I'd been savvy/around at the time. _____________________ ---
Kyrah Abattoir cruelty delight Join date: 4 Jun 2004 Posts: 2,786	05-25-2005 21:00 i experienced some ways to create links that are bigger than the value allowed (i did up to 120 meters) seems the physic really hate it as the linked prims whare almost like phantoms _____________________ tired of XStreetSL? try those! apez http://tinyurl.com/yfm9d5b metalife http://tinyurl.com/yzm3yvw metaverse exchange http://tinyurl.com/yzh7j4a slapt http://tinyurl.com/yfqah9u