27 July 2012
As you have probably heard, Linden Lab is introducing pathfinding to SL. This announcement is not about our plans for pathfinding dogs (although we do have some exciting plans for that which we will begin telling you about soon). At this moment in time, we need to talk about some changes that we’ve made to the way we build the dogs in preparation for the changes that LL is making. You won’t see any changes to the way your dog looks, but you will see that in many cases his Land Impact (LI) has increased. There is nothing that we can do to avoid this in the dogs because it is due to LL’s changes. But there are some simple things you can do to help keep your overall Land Impact down. In fact you might even find that you can save a lot of LI and keep more dogs on your land!
One of the side effects of the changes that are being made to the simulator software means that sometimes physical objects can sink into the terrain mesh and occasionally fall right through it.
In order to prevent this from happening we need to switch over to the new “Mesh Accounting” system which calculates Land Impact (LI). This means that rather than simply count the number of prims in the object, it counts the number and type of the prims and calculates a physics cost based on the shape. It also takes into account the number of scripts in the object. The Land Impact can go up for a complex scripted object such as a dog or other animal made with sculpted prims, and it can go down (often quite dramatically) for a simpler object such as a house or a barn. You will see that our sculpted dogs increase their LI, but most of the old prim dogs decrease theirs.
Question: How big are the increases in LI?
Answer: Here are some examples of what you might expect:
Question: Do I need to update my dog?
Answer: If you are having a problem with your dog sinking into the terrain, updating him will probably fix that. Other than that you don’t need to update your dog right away.
When you do update or reclaim your dog, he will have the new construction and the new Land Impact.
Question: What can I do to help lessen the Land Impact changes?
Answer: There is a new prim type that comes in with the Mesh Accounting system, you may have seen it in the Edit window, it’s called Convex Hull. You can use this to great effect in houses and other buildings to lessen the Land Impact. It works best on things that are just made with simple flat (box) prims like walls and floors and it is not always very good for complicated shapes especially hollowed boxes so you have to use it carefully. But as an example, when I converted the VKC Clinic building to use Convex Hull in the simple prims, it went from a Land Impact of 26 to a Land Impact of 13. So with a little bit of work you can save a lot of LI! It’s like your prims only count for half as many as there are. You could soon make enough reduction to cover the increase in your dog’s LI and probably save enough to get more dogs or animals as we release them! You can read more about Convex Hull and changing your builds.