Things' sizes

So I was designing some Magical Things characters (mainly because of this thread, which ended in thoughts about how to turn your lab into your familiar), and then I found what's going to be my most hated rule in RoP:M. That one who limitates Magic Thing's Might because of their size.

The first time I read it I found it quite disturbing, because everywhere else you can have mighty creatures of small size, but I moved on and pretty much forgot that. But now that I'm back there with my lets-go-design-characters trousers on, I got stuck on the first step. Ok, size limitates might... but what are the sizes of things? Is there any list, anywhere, of things' sizes?

In cause there isn't, I'd been trying to figure something. I know that the basics rules for creature sizes are mainly two: one size steps increases or decreases mass for a factor of 2, and 3 steps does so by a factor of 10.

So, ignoring silly things like density, would it be ok to figure that a sword is something of Size -4 (because it's roughly about 3.4 - 5 kg, so about 1/20 of a human, and thus a magic item sword could have by itself might up to 5)? Or shoud I don't ignore density, and take into account that iron is about 8 times heavier than flesh, and thus if an iron human would have a mass of around 600 kg, swords should be even smaller, around size -7 (and so might up to 4)?

And what about rings? What size is a ring? Gold rings seem to weight around 5 ounces or 140 grams, so size -8, ignoring density, or something as low as around -11, not ignoring it (and might not higher than 3)?

On the big sized things, what would a lab size be? Stellatus' description in the core book says that he's small for a dragon (though at size +8 it's pretty much in the average of other books' dragons, but whatever) but still bigger than most houses, so a average house would be of size 6-7, and thus maybe labs, being big rooms, would probably be at least 4 and probably up to 6, if we consider that labs are large rooms and probably houses where pretty small back then...

So I'm lost in an ocean of sizes and weights. Does any of this seems coherent, or anyone knows of a beautiful items sizes table I forgot about? Or should I just forgot that rule and assign magic might to Magic Items like it's done for any other magical creature?

You'll find page 49 of RoP:F very helpful. As for Size v. weight, consider that birds are 2 Sizes more than their weights would indicate. So volume wins a bit over weight, while both are important.

Marry me, callen!

I'm looking at the numbers there and everything fits... Amazing!

Alternatively, as you're looking at a room, let's look at sizes from the extended material and size table in The Mysteries p97. A room is given as Indx100. By comparison with other size charts in this works out as about size +6.

Note that RoP:M rules on page 32 state a magic thing's might determines its minimum size - so a might 25 elemental can't be smaller than size +6, but theoretically a might 1 magical object can be far bigger than a pebble. If you were trying to rarefy the walls of your room into an earth elemental, you would probably be looking at the might 25 level.

I remembered that. And I was quite fond to find that that pretty table agrees with that: if the standard lab is 500 sq. feet, then it's of the size of a 25' diameter circle. And that table gives size +6 for these 25'. Everything fits!

Yeah, but I hadn't had any problems with the big items so far; the might is more than enough for the items I'm designing.

All my problems are now coming from the negative size items, and it's possible variation. The book says this about that:

So I was creating just a magic sword, and by itself it's size -5, Might 5 (ok, it's low, but I'd found that a magic thing can get a lot of flaws and doesn't need many virtues, so purchasing flaws through Inferiorities can get a decent powers pool; not much penetration, but well, it's a sword, so it's going to get some arcane connections easily to either to his owner and his enemies), but if it gets a human wielder, then it's Size 0, and Might can be up to 15. But then rules are confusing me: I'd think that I should create the sword as an item of size -5 and Might 5, boosted to 15 when it gets a human wielder (and being able to increase its penetration, spend more might activating powers, ok, I get the benefits). But the loosing invested powers part is giving me a headache, as it seems to suggest that maybe I should either create the sword at size 0 / Might 15, and take note of where the 10 extra points of might are spent to remove them if the wielder is gone, or keep it at size -5 / Might 5, and then spent 10 more points in qualities once it gets an owner who goes around wielding it. Or keep it to the might 5 powers, but then I don't know what that "power invested" stuff is all about.

Or, just don't worry about it and design it as you want it to be.

Well Ben, I got into RPGs with Rolemaster, piling tables over rules over tables over rules... the option of not worry too much about the options is by default my last call. So thanks for the reminder.

Finally after definetively too much thinking both options seem pretty nice for different kind of items, either a crown which is pretty much a chunk of metal until someone puts it over his head and it gets power, or the Tolkienish kind of ring that is a pretty mighty thing that goes almost powerless until someone grabs it. So yeah, I'll keep them both and just focus in the items and the stories I can get from them.