1 prim should be 1 Li - Even when it has a PBR
tracked
Coffee Pancake
(see picture)
This is our old friend twisted torus.
Twisted torus doesn't get out much anymore because the moment a modern texture is applied (material or PBR), the Li jumps from 1 to 306
This is and has always been clearly wrong and broken. A texture or six doesn't change the actual impact of a thing by a factor of over 300.
Prims are always going to be heavier than mesh, but keep in mind this was all we had back when our graphics cards had MEGABYTES of memory. Our hair was 200 twisted tori and nothing bad happened.
Why does a texture flip the new calculations on .. because legacy builds would get auto returned en-masse.
For all their sins, please fix prims so they are at most 1 Li under all circumstances.
Prims are accessible, fun and core part of the platform.
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Wulfie Reanimator
Just to further explain
why
the problem is happening currently:The huge change in Land Impact happens because the prim switches to the Prim Equivalency system when certain "new" features are applied to prims (like normal/specular map, Convex Hull shape, or PBR material).
Prim Equivalency is how the sim determines the LI of mesh objects, it's a term that refers to the three stats which determine final LI.
Twisted and hollow prims tend to have quite a complex physics shape. The LI we see
should be
equivalent to the same physics shape made for mesh, but it's usually much (orders of magnitude) higher for prims.If the physics shape of the prim is switched to Convex Hull, the LI returns to normal, but obviously you can no longer walk inside of hollow/cut prims and that's not always a viable solution.
Spidey Linden
tracked
Issue tracked. We have no estimate when it may be implemented. Please see future updates here.
Rheia Silvercloud
A similar behavior can be seen and modeled in hollow spheres - add a material (PBR or non) and it'll jump to anywhere between 80 and 390 LI.
Honey Puddles
I've seen a simple, 4 revolution torus go from 1 Li, to 892Li, just because I added a normal map.
I understand that Torii were always a bit of a 'unfair' model in terms of actual viewer and physics impact, but this seems positively ridiculous, and is at the very least, unexpected and unintuitive behavior.
If this can't be changed, I would suggest that at the very least, primitives that (when receiving materials) have this 'switch' to new accounting drastically affect their land impact, should instead
automatically
switch themselves to Convex Hull, as a standard practice.Users would still be able to switch physics back to prim if they wanted, but perhaps a popup dialog should appear, warning them
"This will cause the land impact of this object to change to 892Li, are you sure you want to do that?"
