Added mesh roof to my house and it lowered the total prims of the whole thing when linked?

[SoranWhite5]

I built a house recently and wanted to add mesh roofing to it, the house is 99 prims and the sections of mesh I want to add are 3x 14 prim, 1x 8 prim, and 2x 4 prim sections. When I added the mesh onto the roof and linked them all to the building it lowered my building's total prim cound down to 85? How does that work and is it really only 85 prims now??

[Dresden Ceriano]

This is difficult to answer without being able to inspect your build, but I can offer a suggestion.  It could be that when linking the roof to your house, your regular prims were converted to Convex Hull Shape Type instead of Prim.  When regular prims are set to Convex Hull, they count as .5 LI, depending on the shape (some shapes increase LI), meaning two prims linked together and set to Convex Hull count as one LI.

You can read more about it here... link.

...Dres

[Lindal Kidd]

Dresden is right!

Changing the physics shape of an object to Convex Hull can be a neat trick to cut the land impact of your builds.  The actual prim count is not reduced, of course...all the prims are still there!  But as far as the land is concerned, you only have a L.I. of 85 "prim equivalents".

There is a drawback to using Convex Hull though.  What this does is treat the object in a simplified fashion for the purposes of determining collisions.  Part of the simplification involves ignoring hollowed out areas.  If you have created a doorway with a hollowed out prim, or made a fence or wall from a hollowed out cube, you will no longer be able to pass through the hole.

And sometimes, using Convex Hull (on a sculpted prim, for example) will INCREASE the land impact of an object.  So be sure to keep an eye on that.