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Size and lag of prims

Vivianne Draper
Registered User
Join date: 15 Sep 2005
Posts: 1,157
09-12-2006 05:42
Hey I have a question. I know the amount of prims will contribute to lag as the the amount gets larger. I know that the amount of textures will contribute to lag as the amount gets larger. Does the size of prims also contribute to lag or even filling the asset server? If not, why is the size restricted to 10x10x10? Wouldn't increasing the maximum size help cut down on the amount?
Kelly Linden
Linden Developer
Join date: 29 Mar 2004
Posts: 896
09-12-2006 08:24
The size of prims may effect client side FPS marginally, although with occlusion culling (which we use) they could actually increase FPS.

They do not use more space on the asset server.

They do cause problems with region crossing and potentially 'popping' anomolies.

Regions in Second Life overlap 5m into each other. This allows for a smoother transition when crossing region boundries. With this system, The largest diameter you can have where the entire object can always be in the same 'sim' (or the part that is overlapping) is 10m. There is a little bit of 'fudge' in there, the transition from sim to sim isn't always instant and of course a 10mx10mx10m cube has a larger than 10m diameter from corner to corner. However these are both small deviations from the 10m basis for the rule.

Also because prims have always been limited to 10m, it is quite possible that larger prims will have a weird 'popping' effect where they don't come into view until you are much closer to them. This would happen because we base the decision to render or not is based on the center of a prim. For large draw distances it may not be noticable. However for very small draw distances and very large prims it is possible that the prim you are running into would never render. I havn't actually tested this, but that would be pretty funny in a buggy way. This last paragraph is speculation on my part, and may not even be true or may be easy to fix, or may not. I just sorta let my mind wander.

Hope that helps!
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- Kelly Linden