I am pottering away on a 3D setting, very much MTU but with what seems to me to be the essential Trav flavour (no FTL comms; neighbouring inhabited systems are about 1 week apart with the basic jump drive).
From various threads here, the key problem with 3D settings seems to be that the number of accessible systems with jump of a given distance goes up much more quickly (exponentially). So a Charted Space sized setting would be compressed into a relatively small sphere and the frontier could be reached from the centre very quickly. e.g. a 10,000 system setting would be contained in a sphere of radius only around 30ly (assuming roughly 12.5ly^3 per system) - if my maths is right (a big if, I fear).
I wonder if this discussion suppresses a key assumption: that every system has to have something interesting in it? If not, your 10,000 interesting systems could be scattered across any volume you like.
Put it another way: let's say I want 40 interesting systems in my 100ly^3 cube sector (40 being about average for an 80 hex 2D subsector with a system on 4, 5 or 6). On average, each interesting system will have 25kly^3 of space to itself.
With a classic 2D map, assuming 50% chance of a system, a hex will have 3 inhabited hexes neighbouring it.
So say I want my system in 3D space to have 3 neighbours accessible under J1. That means I need a volume of 100kly^3 (centre point plus 3 more systems). J1 should cover a sphere of volume 100kly^3; J1 should therefore equal 29 ly (the radius of that sphere). The edge of the sector will still only be about 2 J1 jumps away so it doesn't do anything for that issue, I accept.
Just to help give a nice route feel, I actually use J1=8.9ly (there is a reason, sort of, but never mind that now), giving about 3 J1 jumps between systems - so I make fuel 1/3 the cost and take up 1/3 the volume, and jump lasts 2 days, +/- an error. I can imagine blood pressures rising, so I'll stop there. The point is that the sector I randomly generated in Astrosynthesis came out with a nice route structure (a 5-system main that branches into 2 feeder routes), without fiddling (although you could just fiddle it - as a wise man once said, "after all, you're making this up").
None of this has been actually playtested, except by me in solo play, because I don't have a group (cue violins).
So - what am I missing?
From various threads here, the key problem with 3D settings seems to be that the number of accessible systems with jump of a given distance goes up much more quickly (exponentially). So a Charted Space sized setting would be compressed into a relatively small sphere and the frontier could be reached from the centre very quickly. e.g. a 10,000 system setting would be contained in a sphere of radius only around 30ly (assuming roughly 12.5ly^3 per system) - if my maths is right (a big if, I fear).
I wonder if this discussion suppresses a key assumption: that every system has to have something interesting in it? If not, your 10,000 interesting systems could be scattered across any volume you like.
Put it another way: let's say I want 40 interesting systems in my 100ly^3 cube sector (40 being about average for an 80 hex 2D subsector with a system on 4, 5 or 6). On average, each interesting system will have 25kly^3 of space to itself.
With a classic 2D map, assuming 50% chance of a system, a hex will have 3 inhabited hexes neighbouring it.
So say I want my system in 3D space to have 3 neighbours accessible under J1. That means I need a volume of 100kly^3 (centre point plus 3 more systems). J1 should cover a sphere of volume 100kly^3; J1 should therefore equal 29 ly (the radius of that sphere). The edge of the sector will still only be about 2 J1 jumps away so it doesn't do anything for that issue, I accept.
Just to help give a nice route feel, I actually use J1=8.9ly (there is a reason, sort of, but never mind that now), giving about 3 J1 jumps between systems - so I make fuel 1/3 the cost and take up 1/3 the volume, and jump lasts 2 days, +/- an error. I can imagine blood pressures rising, so I'll stop there. The point is that the sector I randomly generated in Astrosynthesis came out with a nice route structure (a 5-system main that branches into 2 feeder routes), without fiddling (although you could just fiddle it - as a wise man once said, "after all, you're making this up").
None of this has been actually playtested, except by me in solo play, because I don't have a group (cue violins).
So - what am I missing?
