Meshify your world from inside of Second Life – to save on prim cost of houses and other objects

EDIT: Someone’s contacted me saying doing this made their house phantom. If this happens to you and you’ve figured out the details of how / why / what parts – how to control that… let me know so I can add some notes. Going to try and cause it if I can and figure out details. Its a tricky process, results can vary – and takes a lot of fiddling to get to the goal.

A short blog today on a new ‘open secret’ some of us have found since mesh hit the grid.

The idea seems to have been publicly outed by Ciaran Laval.

A lot of mesh content is now getting out there in SL. Not everyone can view it yet – the new viewers have some bugs that are still keeping some folks out, sadly enough. Some of those bugs are mesh, but some are just other bugs… Hopefully that’ll clean out soon and we’ll all be able to see this stuff because some of its plain amazing.

Making mesh though, is another big hurdle. People will tell you to go download Blender and just ‘learn-2-model-noob’. Well that’s not so easy. Nor is spending 10-grand on Maya much of an alternative.

Learning Blender isn’t impossible though… but if you’re like me and not yet there, its not the end of your ability to take advantage of Mesh creation.

In fact, the little secret, Convex Hull – works by turning your prims into ‘mesh prims’. Now the truth is that everything in SL already -IS- a mesh of some kind. Its all polygons and giant files full of weird variables (open up a .obj file someday, they’re text-readable, and pretty scary to try and human eye read. Long ago I had to edit one to find a problem in an art project).

Convex hull means your prim is counted using the new Mesh Cost equations rather than as a 1-for-1 prim, the old “grandfathered in” way.
Two Prims as Prims
Under the features tab there’s a pulldown to change a prim to a convex hull. That turns any prim into a ‘mesh prim’ (there’s a third option called “none” that I have not tried).
Two Prims as Convex Hull

- You can use this to make your own homes into Mesh homes. This is worth considering because if you learn the ‘energy flows’ of ideal prims, you can cut the ‘resource cost’ of a build by as much as half – taking say, a 60 prim building down to 30 or so.

To do this, unlink all the prims, and then experiment with different linksets – convert two linked prims to convex hull, see their cost, add another, see the new costs, and so on. Removing any prim that takes the cost up by than 1. Many will add zero to the cost, others will add 1 on their own or round you up to the next prim cost.

Two basic rules: You CAN do this with sculpties and prims that have scripts in them. But doing so can take a single prim and make SL think its over 100 prims… That’s one of those ‘do not try this at home’ things. Try it in a quiet mostly unused sandbox for the lolz. ;)

- Because if you blow past the prim limit, your item gets returned on you, and you might have trouble rezzing it again if your limit won’t let you…

As for the ‘art’ of finding the ideal linksets that save prim cost; I call it the ‘energy flow’ because if you look at which linksets work best together and which end up expensive, it looks a lot like Feng Sui energy patterns…
- if the lines flow in similar ways, they’ll save you prim cost. If they move about disruptively, meshing them can cost dozens of added cost.

Looking at some ‘mesh houses’ on the market, it looks like they are actually prim houses with this done to them, whereas others look like imports from a 3D application.

Its a good trick to try. Here is the top portion of my house in Ironchurch:

And the same piece, as prims:

But note that the two prims linked above in the first screenshot, when used as a floor in my home had different results:

Curiously I toggled the color of these two to red and white a few times, and that made their prim cost drop to 1. It stayed 1 after I changed the color back to white. I have no idea… I thought it might be because one of them used to have a script in it…

But I applied that script to the two prims in my sky platform, seen in the first screenshots, and that only toggled them between 1 prim without it and 2 with it (treated the scripted ones as if still prims).

In a further complication, see the stairs next to those 2 prims? Well in walking up them a few hours after making this blog post I discovered something else – the bounding box of a cut convex hull is not the same as what is visible. Apparently some of that hollow area was ‘solid’ – I was not sure if I had a mesh problem or a ghosted prim, but by toggling them back to prim, I was able to finish walking up the stairs.
- So test your converted builds to make sure they still work as intended.

So my description for this is getting more and more “its all Feng Shui.”

It very much seems that, as I told a friend; “it you move it so the north wind blows at you, that’s bad. But if you align your corners with the south wind, armies will advance in your favor and the sky monkeys will grant you prims… O.o”

Experiment, until you manage to get your prim costs down.

Also keep mindful of calculation delays and errors. If a value seems off, select something else and then reselect the item. Often values will “correct” after doing this. I’ve seen them jump up double when converted, only to drop down a few moments later. That works both ways. In making my screenshots, I ended up with one showing the 34 prims I had selected, set as prims, with a value of 25. Reselecting them changed it to 34. I know the 34 is correct because I originally grouped them up selecting one prim at a time. In Convex Hull Mesh, they cost 17.

As one more major bonus, non-mesh viewers can still see convex hull prims. I went to my house here using v1.2.3 on my old PC, and everything looked normal.

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3 Comments (+add yours?)

  1. Davedawgg
    Jan 16, 2012 @ 20:58:21

    I absolutely could kiss you. I wont but this is the greatest thing. I tried this on many of my builds and greatly reduced the count. Yippie. It did have an effect on cretain objects like stairs so I just did not do them. I freed up at least 100 proims and am on my way to free up more. Thank You so much…Come visit me in ‘Blue’ (127,126,1) at RDPixelShop


  2. Trackback: Anonymous
  3. Sasy Scarborough
    Aug 25, 2012 @ 03:45:36 this post discusses the none feature and how to use it to make your linked builds phantom but floors not etc. Great tutorial on the Convex Hull thank you.


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