Sand deletes when dug
So I decided to dig a canal of sorts, and although I had no trouble picking up and relocating the first layer of dirt, when I tried digging the sand colored layer that is level with the water (ocean level) it doesn't go anywhere. It just gets deleted. I closed and reopened the game just to be sure.
I thought this might have something to do with ocean level itself, but no, when I found dirt colored blocks they had no trouble being dug and added to inventory - but the sand there also deleted.
So it seems like there is some kind of problem with that block.
known one =) .. waiting for alpha 4 =P
On a related issue, I found that stone blocks below a certain elevation cannot be removed or destroyed - but dirt blocks can. (this of course made it a challenge building a basement)
Although it was funny when I let the ocean in my basement and made it deep enough. I had a whale. Getting the water to flow right without being a complicated set of gravity defying water falls was time consuming though.
"Impenetrable stone" or our version as the limits on the world, currently looks exactly the same as normal stone. So far thats still the case in alpha 4, but we can look into making it more apparent that you can't go deeper.
I thought it might be the limits of the world, but it's not at a uniform depth. Dirt blocks can go way below and beyond these blocks in many places I have seen. On one island this unbreakable block was just a few layers under the surface near the top of where I put my basement and the same elevation of the stone block that could be broken. Since the animation goes on just the same, and expends energy trying, there's no kind of indication of if a block is unbreakable and no apparent pattern to where these are.
The block mechanics are clearly similar to Minecraft, where they use "Bedrock" as the unbreakable. At a set elevation all blocks are bedrock, and there might be random bedrock one space above that, but otherwise you won't find bedrock too high up.
Obviously, you have a spherical world, and when I build a bridge I can see the spherical bend from a distance which is much better than the Minecraft engine, but close up there is no bend so it's obvious that you still have an unfolded XYZ coordinate system that just get folded into a sphere so it shouldn't be too difficult to set a bedrock layer.
Personally, I like underground building, so the most depth that could be added the better. Other players will likely want to push into the limits of the sky. There's going to be some coherent point players can expect to go down and the map should work in layers. I mean, if I build a house at one elevation, there's no reason why a player 20 blocks below can't build a house right under. Maybe one world will want to set up an underground road system that has public use rights, while still allowing players to use the surface of the world.
An idea on that though: What if you set up that "unbreakable" block to actually be "breakable" with a high enough skill level, to build geothermal energy - or, alternatively, a doomsday weapon?
Yeah, its at a variable depth at different points in the world. To be specific, the 'top soil' depth (or diggable/mineable depth) is a max of 25% of the world generation size. This is mostly done as a memory optimization on the server.
So for example if the max world height is set to 100, the max depth anywhere from the surface would be 25 blocks. This is just the way it works now, it will probably change multiple times or be set as a configurable option.
One of the ideas we have floated is having support to dig through the world and come out the other side. How we would handle gravity in the middle (or the whole surviving the magma thing), I don't know - but its an interesting idea that may happen some day.
Digging through to the other side would be interesting, but would definitely require property lines to overlap.
I think a better solution would be for there to be a molten core, with perhaps a kind of semi-unbreakable block at varying depths that requires extra special tools to remove, and then a final block at the absolute depth which can't be broken through, but can have a geothermal device attached to it in pieces or can have a doomsday weapon built to crack the core. Maybe you could also build a specialized tube through the core to create an elevator. Maybe a future space elevator could even tie directly into that, connecting underground cities to surface cities to space colonies.
or... you could go with the expanding Earth theory of geology. I actually have an old geology book that is well over a hundred years old. It was written before plate tectonics as an idea was accepted. According to the expanding Earth theory, the world is hollow, but inflates in size due to meteorite collisions constantly adding mass. In some versions there is a tiny Sun at the center and volcanoes are just heat vents. It's an interesting model to say the least.
Gravity is actually explained pretty simple in that model, using equations that are still valid in physics. Basically, the attraction you feel to the Earth is gravity minus centripetal force. This is absolutely true, and the closer you are to the core the weaker gravity is to you. This is why there is a region of Canada where the gravity is actually lower than the rest of the world. Anyway, the model asserts - wrongly - that there is a point in the Earth where the centripetal force overcomes gravity, so when you get to this point it's more difficult to approach - gravity gets lighter as you approach the line - and then you flip around and start clinging to the ceiling.
If you went with that model, you would have an entire inner world with it's own systems. It wouldn't be a factual representation of the real world, but it does represent old ideas people held and it's certainly more interesting than just ending up on the other side.