Wanted this for years! I call it pocket parcels. Terrain tool allowing traditional parcel cutting and then a new feature to set a vertical height for the parcel. So say we have a family home or a hotel and everyone wants privacy in their rooms, we cut a parcel at the ground and then drag vertical lines upwards to where the ceiling of the new parcel will be and then lift up the lines at ground level to where the floor/roof boundary of the pocket parcel would be, creating a 3D pocket. This can be produced at any height. I think it's a great and needed feature for ground builds and skyboxes. It will benefit and advance SL in many ways. Travel and user quality of life. Another great parcel setting would be to allow the parcel owner to have a parcel derender list so the owner can blacklist objects they don't want in their view or their guests view. Sure we can all derender things personally, but if we invite a guest over they're still going to see whatever eyesore we hid for ourselves. Dying for these parcel features!

Merged in a post from FijiLove Resident:

Title: Dividing the sky

Details: I always wished to be able to "divide" the sky like you can the land. So at 1000 feet I could have a different radio station or permissions. It would be great for folks renting skyboxes.

Parcel naming, soundscapes, & subdivision should all be separate and doable on different levels. I created two totally different themes, one on the ground and one in the sky. I can't rename or parcel areas appropriately. I can't add theme appropriate streams, creating a soundscape yikes. I put in media viewers in the upper level, but the sound was bleeding into other areas, so had to subdivide on the ground and constrain to parcel, which created sound dead spots on the ground level. I set aside space for personal use, but anyone visiting can certainly snoop, radar etc. not a fan of ban lines etc. Trying to create something for the public makes it virtually impossible to create a private area, they see who is there, what is there etc, this should only be the case if someone has been granted access or owns it.

just had similar idea, but, for more than just permissions. divide the space between simulator floor and ceiling into 3 layers... Bottom = ground type, community matching, themed builds. Middle = protected air space for pilots and travelers. Upper = skybox territory. Allow the upper/lower layers to be separate space to be sold/rented. Create a simple covenant for ground territory to keep communities decorated and themed to the surrounding neighbors/communities. People who want strict security can have it, pilots can safely travel the entire grid with no issues and skyboxers can have their stores or hideouts and community minded people can have the ground for themed connected communities and the Lindens and land barons have more space to rent/sell. No more wasted or blockaded space. Everyone's happy.

I would add that some world builders who create regions with multiple levels at different altitudes -- Ground + 1000m + 2000m ... 4000m -- would like to have different music and media streams available at these altitudes as opposed to having to use the same music stream on the ground. Especially with full sim-wide regions that are effectively 1 parcel it would be a cool feature if the region owner could to choose to invert one of the axes to create "altitude parcels". The whole purpose behind parcelling is to rent an X by Y space with Z ranging from 0-4000+m. But what if your purpose is to create fantasy worlds one on top of the other?

I think this would be OK for private regions, but absolutely not for mainland regions, where complexity and abuse issues could cause chaos and confusion.

I've wanted this for years.

For private regions, I'd rather see the ability to have more 'land' at the same number of total prims. If the prim count is the same, there's not going to be much of a performance impact for a slightly larger region.

Land is artificially scarce in SL and it doesn't correspond with actual server or client load. Skyboxes are a hack that wrecks the immersion of SL - I'd rather see it properly fixed so they're never needed.

This seems like nothing more than a way for us to receive less 'property' for our land purchase, and SL to make more money off us. When we buy a parcel, our use of the space above should be within OUR control, not SL's... as it has historically been. There are MANY options for security, if that is an issue... and remember, viewing is always an option, so you really aren't 'secure' anyway... so, don't enter a 'public' space and expect to have privacy.