Here's a megaproject I made in 40d16 late last year, thought some people might be interested.
Essentially, it's a huge floating oblate spheroid, with a side-to-side diameter of 64 and top to bottom diameter of 32. I made it by building the lower half shell out of basalt, then filling it in with obsidian via a lava/water pumping tower thingy; once the lower half was filled in, I built each outer shell layer then filled it in before doing the next. Lava was supplied by a volcano, and water from an underground river. If anyone wants to build their own fortress in the inside of it, I have a save from when the sphere was done but before I started carving into it (if someone could let me know a decent place to upload it, that'd be great).
As it turns out, I built it a bit too close to the lower edge of the map and one side got a bit squished, but that makes it look more like a death star, so I can't complain.
And, without further ado, pics:Construction of the shell
The first five levels of the lower shell: http://imgur.com/2khmI.jpg
The completed lower shell: http://imgur.com/L0x2G.jpgCasting the lower half
The obsidian casting tower: http://imgur.com/0B9hV.jpg
The first layer of obsidian casting: http://imgur.com/lbva7.gif
View from inside during casting: http://imgur.com/WusNI.jpg
It became apparent that the initial casting tower wasn't up to the job, here's the MkII casting tower: http://imgur.com/afw20.jpg
Another angle: http://imgur.com/sAlCU.jpg
And yet another: http://imgur.com/OfZwP.jpg
Side view: http://imgur.com/E85um.jpg
The first layer poured with the new tower: http://imgur.com/4UX6u.gif
Another view from inside: http://imgur.com/usK8e.jpg
Time-lapse filling of the lower half: http://imgur.com/4TGx4.gifThe last layer of the bottom halfhttp://imgur.com/UtFUy.jpg
19 HalfDone.jpgA bunch of pictures from the half-way pointhttp://imgur.com/eEC1d.jpg
The volcano was full before I started: http://imgur.com/yQSgD.jpg
There were a few little holes that got missed when building the lower half, here's the contraption I used to help fill them, along with its deconstruction: http://imgur.com/C7P2n.gifThe top layers
An animation of the first top layer being cast: http://imgur.com/2TjHr.gif
Time lapse of a few more top layers: http://imgur.com/pDYir.gif
A bunch of pictures from when it was almost done:http://imgur.com/NF6Mr.jpghttp://imgur.com/hgUh3.jpghttp://imgur.com/IfpOS.jpghttp://imgur.com/MPVn6.jpghttp://imgur.com/1zjIH.jpg
The last layer and starting the deconstruction of the casting tower: http://imgur.com/rLpyE.gif
A crude fly-by of the sphere after the casting tower was removed. A couple of holes remain: http://imgur.com/Y5cAJ.gif