Growth and Shrinking

Continuing the discussion from Call for ArM5 Errata:

Splitting out for discussion. This does need to be clarified.

Looking at the general size rules, we should probably be working with factors of ten, based on mass/volume.

In that case, if you have a base guideline for growth by a factor of 10, and adding another magnitude allows growth by a further factor of 10, you naturally take account of the size, based on the final product. Thus, there is no need for further adjustments for the size of the result, as there might be if growth were faster.

Going the other way, there is a question of whether we want it to be easier. If we do, then one magnitude for a factor of 100 is probably the way to go, with a base of 100. The MoH spell would need +2 magnitudes, and the HP one would need +1.

This would involve errata on the MuTe guideline, as well.


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That's what was done with growth in MuCo, though the original is +1 Size rather than +3 Size. But for additional growth an increase in size handled it.

That would be your choice first. Yes, MuCo shrinking gets -2 Size as easily as +1 Size, so there would be some consistency there. It is interesting to note that shrinking needs magnitudes for more size separately from magnitudes for more shrinking if we look at the HP spell, while growth doesn't seem to. But if shrinking gets that factor of 100 instead of 10, there is some fairness there. It's still a little confusing that growth gets to merge them, but we've lived with it so far.

MoH. Now, there is a question about the size of a grain of wheat since they vary in area by a factor of about 10. Unfortunately, standardized grains and wheat grains are units of mass rather than volume. Looking at volume, they're typically about 5 to 9 mm in length and about half that along the other two dimensions. Assuming a spheroid for simplicity, this would give 131 to 763 mm3. So 450ish mm3 is a good ballpark. The chest has a volume of 5.625 ft3 = 160 000 000 mm3. So the maximum shrinking is by a factor of about 354 000. 100 x 100 x 100 handles that, so yes, +2 magnitudes would work.

HP. This is simpler. It's reduced by 2700, so yes, 100 x 100 is enough and +1 magnitude would work.

i actually was trying to figure this out last night. I thought that side bar i found in the core rulebook got me to a place of 10 times 10 for magnitude 2.

I'm confused. First, are you talking about growth or shrinking. Second, what do you mean by "magnitude 2" for "10 times 10"? The base magnitude is given by the base, which can vary by Form. The final magnitude will vary from there based on what's been included for R/D/T, size, and maybe other stuff.

well, i very possibly got it wrong.

I was referring to shrinking a very large creature. page 113 about the size of a target making a difference to the level of the spell. Hmm, so perhaps it was two magnitudes for large size x2, plus more magnitudes for shrinking. I thought Mr. Chart was saying above something similar for the shrinking rules, but it's not at all clear to me from the rules.

Ah, OK. Here the base includes the first x10 because that's what the base is doing. David Chart said to be consistent with what you found it would be good for it to be x10 rather than x8 (the minimum required for the spell). Each extra magnitude added on allows another x10. That's why x100 here is just +1 magnitude added on, as it's only one step bigger than the base.

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That is what I am saying, but it is not clear from the published rules — hence the discussion of possible errata. We do want to make sure that the clarifications actually make things clear.