What I propose are content properties:
Make a cube, assign it "indoor", a property similar to "phantom", but with more substance... you'll be able to walk through it, but it will otherwise be treated as an indoor space.
This allows for the return of weather effects, lets us build submarines and other underwater structures, stops wind on otherwise wind-reactive objects... (say, you wanted a greenhouse)
Most importantly, it's a way of finally making locks that work. If your front door script needs a key to allow ANYONE into your house, because otherwise the interior is just an impenetrable cube, that's a lot more effective than just climbing through the wall.
Likewise, with more advanced surface and content properties working together, (when we have the hardware for it!) you could have "jello"... "fur", and so on... there's more uses to this than creating a one-primitive tribble, though. Things like bump mapping, reflectivity, rigidity... (yes, I know these are features a little beyond what we currently have to work with, but hey, I'm thinking down the road.

Still, I at least think an "indoor" content property would be a good idea... you could have properties to mute speech, so you could talk freely within your house, without having to worry about eavesdroppers.. you could set a restriction on the chasecam that only avs INSIDE the indoor object would be able to move through it (just design the content properties feature to allow for overlapping objects... so that an "indoor" cube and sphere with the same owner could exist as the same indoor space. (so that anyone wishing to eavesdrop couldn't just stick a 10m long pole into the side of your house and then stand at the end of it.)
Oh, and if you're wondering how to make the cube invisible, why, a "nodraw" surface parameter would do nicely, thanks.

It occurs to me that another potential use for this would be allowing for a script trigger attached to an object that you could walk through... no proximity sensor, just an invisble wall.
Thoughts?
Catherine Omega