Mixed scale game

[Calnala]

I had an interesting thought on my commute this morning.

My thought was how to run a game in which 15mm(or even 10mm) forces are exploring a large space ship from a race of giants(28mm). (i.e.Prometheus, or other movies that had aliens being much taller but not monstrous in size)

Forces:
1) 15mm all infantry force with portable support are the attackers.
2) 28mm Ships crew/ marine defenders

Board:
The entire board is set for a 28mm spaceship interior.

Issues:
How would the scale difference be handled? Should I start with a sytem for 15mm and scale up or start with something for 28mm and scale down?
   A)Many games say to change from inches to centimeters. Should everyone move the same or have each force move at it own rate?
   B)Would all weapons keep the same damage and just give the figures a toughness modifier. OR should it be the other way around?

[Pictors Studio]

I think if you looked at something with big stompy robot rules you would have a starting point.  A game like Epic from GW would allow you to have your infantry in the smaller scale and your big aliens, like Zentradi, at the larger scale be like titans in the game.

Or check out the Robotech game, that has large scale aliens, as mentioned above, fighting against humans, although in that case it is humans in big stompy robots and fly-ie robots too. 

[v_lazy_dragon]

Lots of Sci-fi rules have bits to cater for 'ogre' sized creatures - be they Ogryns, Tyranid warriors, etc
That might be a good place to start looking? Seems to be that movement can be faster (big steps) or slower (lumbering compared to small skittering folks), the figures are often tougher and/or have multiple wounds. Set your 'human' size to 15mm, swap the scale to cm's, then apply the 'big creature' rules to the 28mm's? (15-18mm to 28mm probably isn't too far off 28mm to 40-50mm 'Ogre'  size relationship anyway)

Alternatively, something I was looking at for fantasy games - is multi base the small folks and use them as a single figure in 28mm rules. I was going to have 3x 15mm 'people' (elves, fey, call'em what you will) to a 25mm round base. Would move the same as a 28mm figure, take the same number of wounds/toughness as a 28mm figure (one might sweep of the sword would kill 'em all. Counter the toughness as 'armour' from being harder to hit) but would instead do 3 weak melee or ranged attacks compared to 1 'normal' attack (i.e. if normal attacks wounded on 4+ on a D6, these guys would wound on a 6+). Seemed like a simple solution at the time

[Jagannath]

Solely from a modelling perspective - this can be quite difficult. I had a similar thought for some fantasy stuff (an abandoned ‘giant’ City) which sounded cool in my head, but your eye doesn’t work like that when you look at the minis: it just looks out of scale. I’m still pondering that one.