linked prims and material type

I guess people don't pay a lot of attention to material type when building. Material type only seems to affect a few things. Density (and thus mass) of prims and lighting effects are the two major ones. There are a few more subtle things, like rubber is more bouncy and glass has less friction.

And of course, there is the impact sound. Walking on wood sounds different from walking on stone, and so on. In a recent bulid I took a lot of care to make sure all the brick foundation prims were made of stone, while the wooden floors and walls were made of wood. Walking up stone stairs and wood stairs sounded pleasingly distinct. Then I linked everything up, and lo and behold everything sounded like stone.

It seems that the material type of linked prims are all effectively the type of the root prim. I've noticed this before when working with lighted prims in builds - strange things happen. Am I doing something wrong? Is there some way to have different prims in a link set have different effective types, or is this an inherent limitation of SL? If it's a limitation, is there any hope of having it removed in a future release? Will it require Havok 2?

I know it's possible to have individual child prims of a linked set change from <light> to <wood> without affecting the rest of the set. And from what I remember, the same is true for the other material types. Of course, I'm changing materials mostly with scripts, so maybe the linking process reverts materials to the root material? And, I've never paid attention to the sound and physics results, but the <light> material is definately not related to the root prim. Try linking, then changing individual prims again, though I don't think that's necessary.

Then again, maybe you're saying that the linked child prims indicate the material you originally set, but act with the root prim's material once linked. I can't test that since I'm at work, and haven't enabled local lighting in a while. But, <light> child prims still appear brighter and shadowless independent of their root prim's wood setting, in my experience.

Hmm, I never noticed that before. I'm going to guess that it's probably a problem with the density. I have no experience with Havok, but I'm going to go out on a limb here and guess that it's probably not designed to deal with variable-density objects, just mass as a constant throughout the entire object.

The problem with the collision audio, though... that's something they definitely shouldn't have overlooked.

Unfortunately, given past experience in asking the Lindens about improving some of the more horrible aspects of linking objects together, the Official Response is likely to be, "that's a good idea, but because of <reason>, we'd have to rewrite a major part of the physics system to do this, and we'd rather do it after Havok 2, so we don't have to do it twice."

Honestly, whoever thought that it made sense to have a single control to set luminosity, collision sound, object density, and fullbright lighting was on drugs or something. Hmm, why do I get the feeling that they're also the one who wrote the hardcoded QWERTY/US-101 keyboard code?

I guess the best advice I can offer is to consider linking your structure in two or three modules, depending on the appropriate sound. To make it easier to move around, consider linking a single prim as the root object, and just have it at the same coordinates for each one. (Choose different widths and thicknesses for ease in selecting when you link, or integrate it into a window or something.)