Land of (Impact) Confusion

I’ve been spending a fair bit of time on the beta grid lately, mostly getting frustrated that I can’t make one mesh face on my mesh object a 1:1 ratio when I texture it, but that can wait. I really like the new upload tools, they make everything far easier to follow regarding level of detail etc. However tonight I decided to play with checking land impact figures. Land impact replaces prim equivalency on the beta grid, indeed it replaces all previous settings for counting objects in the about land settings! However don’t panic, legacy prims and sculpts will largely be protected…. I think, the further I dug into the murky world of land impact, convex hulls and prims, the more confused I got!

I started with a simple mesh object, which on its own has a land impact of 1:

I then duplicated it and got ready to link the two objects:

I then link the objects and as expected I now have a two prim linkset with a land impact of 2 .. oh wait no I don’t! The land impact score is actually 1! The advanced window displays the full information:

So Mesh items can have a land impact score of less than 1, but this only works when you link them, nothing on its own can have a land impact score of less than 1. How does this compare with sculpts and prims then, I hear you say….those of you haven’t nodded off already that is. Well comparisons aren’t easy because my comparison items are different shapes, but legacy items by default appear to be keeping their legacy scores, I have some nice sculpty stairs, they are two items with the bannisters and come in at 5 prims traditionally, on the beta grid they also have a land impact score of 5:

So land impact is showing nothing alarming about my sculpty stairs, I’m not going to run out of prims when land impact arrives, but wait, my mesh objects are set to convex hull, these stairs are prim, so let’s change the stairs to convex hull and watch the results:

Whoa! Land impact score is now 14! The moral of this story seems to be not to piddle about changing sculpts to convex hulls, especially when you’re not sure what the bloody hell a convex hull is in the first place. However this is hardly extensive testing, it may well be that some sculpts will benefit, however as they are considered legacy items and not under the same weighting rules, they may not …I warned you this was confusing.

However let’s take a simple Mesh Building:

That’s 10 prims in old money terms, it has a land impact score of 5 when I leave it as a convex hull, when I change it to prim, it has a land impact score of 5 still:

Now, I know from piddling around on the beta grid that changing a mesh object from convex hull to prim can change its land impact score, so maybe there’s some quirk on the beta grid with linksets, I expected the land impact score to change to 10.

So finally I went back to the lovely prim cube, I love prims, wonderful invention, gives everyone an equal chance. I rezzed two prim cubes and joined them, checking the advanced link to really show what’s going on:

Two prims, land impact score of 2, I then changed them to a convex hull, now remember when I did this with my sculpted stairs the land impact more than doubled, so what delights would standard prim cubes converted to convex hull have for me?

So now they are working like my mesh items and I’ve managed to half my prim count! Hurrah! Long live The Prim!

What does this all mean? I’m buggered if I know but it’s important to keep your eye on the land impact score, when it eventually arrives on the main grid, changing from prim to convex hull may or may not save prims and may or may not work for the type of item you’re creating and finally, it’s all very bloody confusing but I’m sure something good will come out of it all!