Custom Twilight Imperium RPG, hex size in LY?

By captaincutlass, in Twilight Imperium 3rd Edition

Posted at

After several years, I've decided to revisit my custom made Twilight Imperium RPG. In the past I've used Spacemaster 2nd edition So I'll be using that again with some additions from Gurps and Traveller.




I've also created a site for my players and (anyone else interested). There are no rules posted there so you could use it with any system you like, there is still quite some work to be done there though. Check it out here: http://spmti.weebly.com/ any ideas, comments, critique or other feedback is greatly appreciated. so please tell me what you think about it.




At the moment I'm creating a galaxy map for my players so we can quickly figure out distances and travelling times. However I have no idea on how big it should be. I've always had trouble imagining such vast scales. I had the idea to have each system tile be 5 or 10 light years but perhaps this is a bit small?




For larger distances my players would have their ship ride along with a carrier, just like in the boardgame.




Here my current prototype of the map:









Please help my figure out the scale?




Thanks in advance, and also for any other ideas or feedback.




Arr!




Posted at

"In the Milky Way, the average distance between stars is about 5 light years, or 30 trillion miles."

http://lithops.as.arizona.edu/~jill/EPO/Stars/galaxy.html

Other galaxies and other types of galaxies (e.g. globular) have other averages.

Posted at

I don't think that the TI hexes were really designed to be used in any particular "scale." You're probably best off just deciding for yourself how big you want one hex to be. 5 lightyears across sounds like a nice round number, and should serve the purpose of any space-bound RPG nicely.

Of course, there's no way that a single supernova star would cover 5 lightyears. Nor an asteroid field. You could argue with good reason that each planetary system sits within a 5 lightyear "sector," however the vast majority of that space would be empty with a star somewhere in the middle and 1 to 3 habitable planets in orbit.

An alternative would be to make each hex the size of a single solar system, which ought to fit the hazard hexes a little more nicely and it would mean the planetary system hexes are mostly occupied (astronomically speaking.) The problem with that is that you'd need a WHOLE LOT more hexes to make the distances between systems realistic. In fact, you'd probably want to replace most of those hexe son your map with red "hyperspace" hexes that have a different scale or something, because it's just not practical to keep it all in realspace.

The diameter of our solar system depends on where you measure to. If you measure to Pluto's orbit (never forget!) then it's about 40 Astronomical Units (AU). 1 AU being the distance from the sun to Earth. 40 AU is about 0.0006 lightyears, for reference. However, there are comets and such in orbit around our sun that are further out than Pluto. If you measure to edge of the Oort cloud - the furthest objects recognized to be in orbit of our sun - then the solar system's diameter is about 100,000 AU (0.0015 LY.) So even measuring out to the edge of the Oort cloud, you'd have to increase the size of your map by about 1000 times and space everything out accordingly to make it to scale in realspace.

TLDR; Douglas Adams wasn't fooling when he wrote that "space is really, really, unimagineably big." At the end of the day, your players won't know the difference if your scale is off from reality by a factor of 1,000 (unless you play with astrophysicists) so just pick a scale that sounds good on paper and run with it. If 5LY is the average distance between stars in our galaxy, that's as good a number as any.

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Thanks both for your insights. I've decided on 20 LY per system tile,

My newest prototype:

SMTI-Map.jpg

Currently I'm trying to make a google API map of it.

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You could look it as warplines - There is no traveling the vast gulf between stars, only jumping between known systems. This solves the problems of 2d space, of how a destroyer can pin down all movement in a tile, and what a supernova is - it is a system on fire. It also shows why there is an edge of the galaxy - noone has plotted the jumps.

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20 seems too far to me. The previous suggestion of 5 would feel more likely. Or 10.