A basic way to speed up building- different liquid materials that solidify into solid blocks, letting you build frames and easily fill them in- helpful for floors and thick walls.
Possibly requiring some kind of machine block- place blocks in it’s inventory, provide it with power and then watch as it pours.
Could possibly use a modified version of water-flow. -drops liquid in the space below, and stops working if that space becomes blocked.
Beacons would need to block this liquid from entering.
I think if a lot of time is spent gathering materials, there should be ways to speed up building- or at least make the more mundane filling in of areas less tiresome, letting you focus on fiddling with details and designing your structures.
Another tool I was thinking of was like a “tron” block placement, where you start setting down blocks automatically behind you. That way you can mark areas with blocks just by walking over them.
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