#SecondLife Land Impact Costs to Change

Friday Falcon Linden made a late appearance at the Sever/Scripting User Group meeting. He announced with the coming of Pathfinding we will see a change in the costs associated with Land Impact. In no small part the change is being influenced by PATHBUG-69.

The Brain behind Torley?

PATHBUG-69llVolumeDetect(TRUE) is broken. According to the wiki:

If detect is TRUE, VolumeDetect is enabled, physical object and avatars can pass through the object. This works much like Phantom, but unlike Phantom, VolumeDetect objects trigger collision_start and  collision_end events when interpenetrating. Collision events will trigger in any script in the object.

In the JIRA Maestro Linden points out the correct way to accomplish creation of non-physical prims in link sets. Setting objects to non-physical is one way to reduce the Land Impact cost of items.

When an object is linked, the prims of the linkset should have a consistent state for linkset-level properties, such as settings for phantom, physical, temp-on-rez, gravity, etc. The root prim’s settings should be applied to rest of the linkset, upon linking. It was a bug that a volume-detect-prim remained ‘phantom’ after being linked as a child prim of a linkset, and that bug is now fixed.

This bug fix can drive the Land Impact cost of linksets up. But, Falcon said, “…changes to Land Impact that you’ll actually like for a change!” So, what we get with the PATHBUG-69 fix is:

We’re changing streaming cost for prims to be capped at 1.0 and we’re changing server weight to be:

0.5 * num_prims + (0.25 * num_scripts)

But capped at num_prims. So, instead of going from half prim count to prim count by adding one script, it will be a more gradual change to encourage fewer scripts.

Falcon gave us an example to make that clear…

Consider a linkset of 3 distorted tori. The two child prims are shape type NONE and the root is convex hull. Currently this would give us the object values:

  • Download weight 13.7
  • Physics weight 1.6
  • Server weight 1.5 – with a script 3

These values result in a total Land Impact cost of 14.

After Pathfinding is released and the Land Impact system is updated, the download weight will go from 13.7 to 3. Under the current system if one adds a script to the object the Server Weight goes from 1.5 to 3. With the equation above in use that changes to 1.75. So we have:

  • Download weight 3
  • Physics weight 1.6
  • Server weight 1.5 – with a script 1.75

The Streaming or Download weight is capped at 1 unit per prim.

This change is still just a proposed change in the system. However, there is a consensus among Lindens that this change is needed and will be implemented baring any unforeseen problems.

If I think about it I can see where this adds incentive for a more conservative use of scripts. As it is now, adding scripts is an all or none type deal. So, once pushed into adding a script one may as well add several. The change should change things to an: add as few as possible deal.

I see this as a significant reduction in Land Impact costs. Both the Lab and Second Life ® users will see a win on this one.

9 thoughts on “#SecondLife Land Impact Costs to Change

  1. Pingback: Land Impact Costs To Reduce ? - SLUniverse Forums

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  4. That could be interesting, if display weight is capped at 1, I don’t need LOD levels in meshes anymore, one mesh, 1 display weight. Otherwise if this don’t count for mesh, and count for sculpts, we can throw mesh away and just use bunches of sculpts. I see chances for roasting falcon on a stick… In the end if it also works for mesh we probably really don’t need LI accounting.

    • No… I think you misunderstand. LoD affects on server weight did not change. Only the affect of scripts changed. You still need to deal with LoD.

      • told you so:) see in your newsweek 18 entry.
        To LOD: i need LOD in meshes to get the values low, if it get capped at 1, i wouldnt need that anymore, but as stated in the news entry (18) its work in progress and meshes are not capped, so again meshes get a punishment compared to sculpts (maybe).

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