Basement Living

Is it possible to have basement levels on Second Life? In other words, true Z=0 construction that is invisible on the X,Y grid?

Thanks.

You can put prims down there, but as far as I know, physics will keep things and avatars above ground. (^_^)

You cannot be below the ground surface (well you can, but only a little way and only if sitting on something).

The only way to have a basement, or an underground room, is to lower the land where you want your room, build it in the hole, and then roof it over with prims textured to look like the ground.

Of course on the mainland where you can usually only go up or down by 4m, you won't get far underground, but on an island you can have several levels of underground rooms, but the roof has to be prims, you can't get under the actual ground.

Great responses. Thank you so much.

You can on islands that allow terra and full terra sims mainland sims that are really expensive. Otherwise you can't sink land directly down very far. I have seen some really nice homes built into false prim hills and stuff like that.

Take a look at Avaria Kro for an extreme example. The whole sim is sunk down and roofed over with prims to create underground caves & lakes.

I have a gallery in a concrete bunker under my lawned garden, which is made from prims and is at about the same level as the surrounding land.

I have a basement area under my castle that is 50 M deep. *grins*

Yes, you can do it. As others said, building underground involves making open-topped pits and/or trenches, and roofing over them with prims.

Limiting factors:

Terraform limits in your sim.
Most mainland sims have a limit of +/- 4 M from where the Lindens designed the terrain surface to be. Some mainland sims and most private island sims have wider ranges. But you can't lower (or raise) your terrain more than that terraforming limit allows.

Water table.
In most sims, there is a flat plane of water at 20 M elevation. Anything below that plane acts as if it is under water, visually and for avatar movement. You can't remove this water from a hole that you make. (For example, the bottom 10 M of a 50 M deep excavation is filled with water, if the terrain surface is at 60 M and water plane is at 20.)

Zero is as low as it goes...
You can't ever set a terrain level lower than zero Meters, even in a private sim. So even if you own the sim, and set the water plane to zero, when you dig down to the zero meter height, you can go no deeper, regardless of terraform limits.

No "tunneling".
You can't dig sideways, under the terrain surface. All excavations are open-topped because you are just streaching the terrain surface higher or lower.

No vertical sided holes.
All holes will have at least a 1 M outward slope. They can't have sides that are straight up and down. The terrain grid only has control points spaced 1 meter apart in the X and y dimensions, and you can only adjust those points straight up and down. You can't move them side to side.