Wednesday, April 16, 2008

The Campus System

Do you realize that every full sim has 268,435,456 cubic meters? That's right, with the new 4096 building limit there are hundreds of millions of cubic meters of space. And yet, because of narrow mindedness, many builds and builders are not taking advantage of what this means.

Consider that this means that even with 1000M between levels, it is possible to have three levels, each one forming a separate campus. Before campus systems, like Yedo's, created the interference with the sky problem, that with Windlight, is a particular concern.

The campus system simply uses a 256x256 solid prim as a floor, and then builds normally. When 768 was the limit, the trade off was having a floating high prim, which could be disguised somewhat, in return for having a great deal more space. However, with the new limits, a three tier, ground/middle/upper or two tier ground/upper system is now not only practical, but has compelling advantages. The most crucial being reduction in prim density while maintaining a physical plausibility and continuity.

The reason this is important is that a large part of client lag time, and user experience, is based on prim density and texture density. Prim density is how many prims are in the renderfarclip, or draw distance, of a client. Whether occluded or not, these textures and prims must be loaded. The twin tendency to pack prims to a sim's limit, and the faux-realist impulse of putting everything on the ground, meant that it was impossible, is impossible, to wander around these sims at more than 64M of draw distance.

This is because most people, including many highly paid builders, do not understand the concept of prim radius. The prim radius is the taken by the number of prims that a particular client can load, divided by the prim density. This density is really an amount of time to load, which is a factor of number and size of textures and prims. More prims, with more textures that are larger are slower. People set their draw distance down to their prim radius, or to their level of pain tolerance for loading time. People who play SL on large fast machines with geekgasmic video cards see SL differently from people who play SL on laptops and smaller machines.

This concept means that very packed sims do not have a "better" experience, but instead begin to break up into very small areas, and become claustrophobic. This increases perceptual size to some extent, because it takes longer to cross the sim, but also increases frustration. Particularly for stores. Packed sims have people wandering in 64M bubbles.

The old campus design created more openness, at, again, the cost of faux-realism sense of geography. Now that this limit is easily avoidable, the advantages of spreading prims out over larger areas, and therefore reducing prim density. This means even slower machines will be able to have longer draw distances, and be able to see greater effects and distances. Combined with huge prims and core and floor design this allows for dramatically large spaces and more focused ornament.

In summary, the 4096 limit should be used to dramatically decrease clutter and prim density, increase the amount of raw land area in a sim to 32 or even 48 acres, and improve perceptual lag while increasing usable client renderfarclip, without detracting from the sky effects of windlight.


  1. >_>
    Well I run with my draw distance set to 512 quite often, except in a few certain sims... Makes a very nice viewing experience... and as I mentioned in another post of yours Lilie I can find laptops capable of doing nearly as well as my custom desktop for under $1000 USD... Since my desktop cost $1500 USD, I don't see that as a bad price at all...

    Also their are some very nice city imitation sims (SICK and Midian come to mind first) that can be slow for the issue you talk about, but it really doesn't bother the experience of those sims...

    While I'm all for improvements of the user experience, and in fact I think my house probably does pretty well, I think you overstate the problem due to purchasing a sucky laptop for this purpose..

  2. Many of us don't play on desktops dear:

    In fact, laptop sales are on pace to "eclipse" desktop sales this year.

    I play on a macbook from last year, whose only problem is that the microphone doesn't work well (I have an external USB microphone).

    I also don't live my life tethered to my desk.

    I've *escorted* in coffee ships and libraries.

  3. As I said, it's a matter of knowing what to buy... And I don't mean desktops vs laptops, as I said plenty of laptops that aren't expensive can run SL as well as the majority of desktops can! Having worked in retail I can just tell you most people are clueless about what their needs are when buying PC's of either type... SO they buy PC's that aren't as capable as they end up wanting and then complain...

    This includes status symbol Mac's just as well as more 'generic' PC's.

    I'm not trying to be mean to you in any way, but when you talk about some of the limitations on what can be done in the client like draw distance you sound like no laptop can run with settings as high as my desktop, or that any laptop that can is hugely more expensive...