#SL Content/Mesh UG News Week 9

No meeting last week because of Presidents Day in the USA. This week’s meeting was short but had a good turnout.

Land Impact Costs

Vincent Nacon is trying to produce a info status for 3D Max users so they can see a mesh model’s weight while it is in 3D Max. There currently seems to be a disparity between the equation on the wiki and the one used by the viewer’s uploader. The Lindens are looking into it.

If anyone else has models that do not match with what you think they should be, get a copy to Charlar or Nyx. That of course assumes you know what you are doing and understand what the uploader is supposed to be doing well enough to recognize a problem…

Convex Hull Link Sets

I didn’t know what they were talking about… It is about changing a prim link set to use a convex hull for the set’s physics shape. In many cases the change will reduce Land Impact costs. When attempting to do this with a prim torus or sculpties it can drive the land impact up.

There are lots of factors involved and not much official documentation. Davido Chrome collected a bunch of information and made a forum post about what he had learned. You can read it here: Information about physics optimization – lag reduction and Mesh. In the thread is a reference to an item in the SL Knowledge Base: Best practices for creating efficient collision volumes. For those making vehicles, it should be interesting… in a geeky sort of way.

Davido gives an example of what is possible. Davido wrote, “Interesting fact, I made an elevated turn [in a race track] from 21 prims. By adding an extra prim with physics shape none I make the linkset use the new Land impact system. The turn is still 21 prims, but it has a land impact of 11. … The same way I can make a 3-prim 64 meter straight with two prims for safety fence have a land impact of 2 by adding a hidden prim with physics shape none. 4 Actual prims, land impact 2.” That is a significant prim count savings.

Kwakkelde Kwak notes another option writing, “BTW, you don’t have to add that extra prim with “none” to let the object use the new land impact system,setting the physics of your boxes to “convex hull” will work aswell.

The Lindens are encouraging people to move to this new system. It shifts prims from the old prim accounting system to the new Land Impact system. But, it offers a substantial savings in lag and prim cost.

Mesh Deformer and Policy Changes

Charlar points out that the Deformer is a viewer feature, so Oz is the authoritative source for such information.

One of the TPV Dev’s commented that Oz is looking for someone to help merge the Deformer 0.2 into the Deformer Project viewer, which is based on the current Development Viewer. Word is Qarl is busy and won’t be able to get to it for a time.

Mesh Stats

Current mesh adoption stats:

70% of online time is with a mesh viewer over the past 3 days.

65% of all sessions are launched with a mesh enabled viewer, over the past 3 days.

73% of unique residents logged in with a mesh enabled viewer, over the past three days.

Charlar says while the trend up until now has been positive, the past few days saw a significant increase in the trend.

The amount of content uploaded each day has far exceeded the launch bump seen at mesh release last August, running up around 1,700 items a day and still trending up, as are the number of unique uploaders, trending close to 500 a day.

I think these are pretty impressive stats. If we can ever get the Mesh Deformer completed, I think we will see an even more significant increase in the rate of mesh adoption.

2 thoughts on “#SL Content/Mesh UG News Week 9

  1. Here’s a tutorial I did a month ago on convex hull:


    And here’s something from last week about Land Impact of mesh:

    – which illustrates that its not going to be ideal to try and guess it before its in SL. As the final land impact is based on the size you rez it at in SL.

  2. About Convex Hull there is another useful tutorial here: http://lagalleriasl.blogspot.com/p/prims-land-impact-by-jenni-darkwatch.html#!/p/prims-land-impact-by-jenni-darkwatch.html
    I tested this new Land Impact accounting system with one of my own 70 prims-building. Shifting from Physics Shape Type -> Prim to Convex Hull, LI dropped from 70 to 35 (same value also after setting to Prim 4 hollow prims of this linkset).

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