Sculpties and lag.

Do sculpties cause lag? I am using sculpted pillows for people to sit on in my club. The sculpt map is 64 x 64 and i am only using the same pillow over and over. Will too many of these pillows cause lag or should i be using a torus instead?

A (unique) sculpted prim with one (unique) texture ON it might cause less lag than a prim that uses 2 different (unique) textures on it.
Sculpted prims only cause a higher loading time and cache if you use many different of them. Just like many different textures need longer to load and eat more cache.
A sculpted prim only uses slighly more loading time than any prim that uses one texture on all faces, but the +1 small texture is barely significant.
Parameters of a prim are set in a list, and sculpted prims need a few kilobyte less parameters in that list.

It are the textures and the KEY adresses of textures that cause loading time NOT the algorythm to display the textures and shapes.

render time can be affected by overuse of sculpties, as they have more polygons than most other prims. the tradeoff would be the point at which they can do as much of more than several normal prims, which would vary by the design.

Using a bunch of identical sculpties shouldn't be much of an issue. I built a home in a class 5 sim not too long ago, that had literally hundreds of identical acorn-shaped sculpties as finials on the staircase posts and bridge railings. They would all rez at once, as soon as the texture for the sculpt map rezzed, and I never noticed a hit on performance from them.

Void's comment on poly count is a good one, however. Any shape that is more complex, like a tube, a torus, a twisted cube, or a sculpty, will have a higher poly count and will take a bit longer to render than a plain cube would.

Is not only a matter of lag, but a matter of video cards and memory too. Once the sculptie is loaded... it doesn't generate lag, but if it is very complex (too much polygons) it will make a big use of you video card.
And if you had an onboard or a not very good one you will note that.

When I first started using Sculpties, I was still on a Mac Mini with only 32 MB of VRAM on an integrated video card. Pathetic SL performance. The main problem then with Sculpties was that they took forever to initially rez.

I started out on a laptop with a Mobile Intel 945GM Express Chipset graphics card--it's actually unsupported. I still use it on the road, and sculpties have never really been a noticeable issue with it (no more so than anything else). Now, walking into a store filled with a different texture on each vendor, quite possibly all 512s, THAT makes it all freeze up.

Sculpties to me are spheres in weird places that you can walk through.

Sculpties have 2048 polygons each. Compare that with the poly counts of the most commonly used prims, and sculpties are huge. A cube is just 108 polygons. A cylinder is just 192. Spheres have 528. Tubes have 768. The only prim that has as many polygons as a sculpty is a torus. Everything else has way, way less.

From poly counts alone, to cause as much of a performance hit as a sculpty, you'd need to use 19 cubes, or 11 cylinders, or 4 spheres, or 3 tubes. By usage, my observations have suggested that the "average prim" has about 188 polygons in it (cubes are used the most, cylinders the second most, spheres the third most, etc.). That means that on average, it takes 11 prims to equal about as many polygons as are in a sculpty.

So, if one sculpty can take the place of 11 prims, then from a poly-count standpoint, it's worth using. If it can't, then it's not.

However, when you factor in that one prim can have as many as 9 different textures on it, it's hard to say where the real balance point is. Since it's relatively rare, at least for me, to have anything close to that many textures on a single object, I tend to feel the 11:1 ratio is pretty solid. Not everyone is what we'd call texture efficient though. If someone's the kind of lagaholic bonehead who loads every surface with an individual 1024x1024 texture, then the regular prims could possilby each cause more of a performance hit than a single single sculpty.

Anyway, if you want to see a really good example of sculpty enduced lag, go check out the Luskwood tree, if it's still there. The thing is the ultimate in modeling inefficiency and irresponsibility. It's a single giant tree, made out of hundreds of identically sculpted and textured pillow-shaped blobs. Even though almost all the sculpties are the same, the shear number of them pushes the poly count of the tree to over one million. It's enough to lag everyone within a 2-sim radius.

It could be worse though. If all the sculpties in the tree had unique maps and unique textures, the problem would be compounded.

However, that's not to say that putting unique maps and textures on every sculpty is necessarily a bad thing. It's all a question of volume. Were the tree modeled efficiently, that tree would probably be hardly laggy at all. If each sculpty were modeled to form the shape of a particular part of the tree, rather than being just a generic building block, each one could probably replace at least 4 of those pillow things, maybe as many as 16 or so. (I don't remember how big they are.) That would cut the poly count (and the prim count) by anywhere from 75% to 95%. Instead of hundreds of sculpties, we'd be talking just a few dozen to maybe a hundred at most. In that case, even though each sculpty would have a unique map and a unique texture on it, there's just wouldn't be enough of them present to cause anywhere near the amount of lag of that million-polygon monstrosity.

So, the final answer to your question, Felix, is that yes, sculpties cause lag, just like EVERYTHING causes lag. It's up to each of us to use every tool responsibly. Anything used irresponsibly will cause more lag than it should. That includes textures, scripts, regular prims, attachments, sounds, animations, and yes, sculpties (and anything else I might have forgotten). What's important is to learn the fundamentals behind how these things work, so you can know how to use them efficiently and responsibly. To keep SL as lag-free as possible, use every resource well, and don't abuse any.



P.S. Anyone out there who's finding that sculpties take too long to rez for your liking, turn up your maximum bandwidth setting on your network tab in your preferences. If it's too low, those sculpt maps can take a while to trickle in.

Thanks for the replies. I never considered poly counts to be an issue until reading some of these posts. So it sounds like, if you can use regular prims instead of sculpties, you should. Atleast in my case I probably have 30 identical sculpties in use so that is alot of wasted polygons.