a more powerful version of Object of Increased Size?

Games Discussion Ars Magica
1

hi folks,
I was looking at the MuTe spell Object of Increase Size and wanted to alter it to have greater size change and perhaps affect larger base items. The current description affects anything up to the size of a large chest, and doubles each dimension and multiplies the weight by eight. My suss so far is:

  • the base effect is MuTe4, for eight fold increase in volume (as per guideline).
  • affecting up to a large chest in size (base Ind).
  • requisites at cast time (free) for the Forms appropriate to the target.
  • then add all the R:Touch, D:Sun, T:Ind mods (as normal).

Questions:

  1. I'd assumed that the intent of Object of Increase Size is to increase the size of a range of things, such as rocks, chairs, weapons, or any other things.
    It makes no mention of the extra mags needed to affect dirt vs finished wooden products, or metal products; which typically have additional mags to affect with magic. Is this a factor that is assumed to be included in the "at cast time" mechanics, or will the effect function as is?
  2. How to handle a change to the original target size?
    Each +1 mag adds an amount of target size, but should I use the 8x fold increase of the effect, or the more standard 10x times the size from other guidelines?
    I'm tending toward the 10x target size as that is how most other effects resolve this due to it being 10 individuals. ; which means the large chest expands to something the size of a large cart or moderate sized boat? This comes back to the idea of paying for the object to be affected with magic, and then also the final size of the object in the spell magnitudes. 10x or x8?
  3. How to handle the expanded final size?
    If the base effect allows a 8x increase in mass, then does each mag adds a further stacking x8 increase in mass? Or is each mag an additional 8x mass?
    eg. a change in mass of x1, x8, x64, x512, ... or ... x1, x8, x16, x24, x32
    I'm tending toward the first set of multipliers, given the way that other Group and Ind sizes tend to expand very quickly (x1, x10, x100, x1000).

Opinions, suggestions, corrections would be very welcome.

2

I think x2 is a lazy way to say x2.15. The extra 8% don't make enough a difference to be worth handling. If you a did an extra magnitude, you'd get x4.64 which might be close enough to round to x5.

So: x2, x5, x10, x20, x50, ...

3

My current house rule:

Making Stuff Smaller or Larger: Changing the Size by +1 is as hard as changing it by -2. Each extra magnitude allows +1 to Size or -2 to Size; in Terram, it instead doubles (or divides by four) all dimensions.
Enlarging people (Muto Corpus Base 3) increases Size by +1 and hence increases wound ranges, but it does not change Characteristics. Using Base 4 [like the MuAn base] also increases Strength by +2 and lowers Quickness by -1. Each extra magnitude allows another increase of +1 to Size, and also allows adding another magnitude to alter the Characteristics again, adding another +2 to Strength and -1 to Quickness.
Two spells to change size that alter it in opposite directions, +X and -Y, work simultaneously to give a Size alteration of (+X-Y) while both are in effect. If one fizzles, and the second remains active, then only the effect of the remaining one remains.

4

One way of looking at it is that a x2 increase in linear dimension / x8 increase in volume is less than a ten-fold increase in size. Since the base spell has no magnitude included for Size it can't go as high as x2.15 linear / x10 volume, but can get close.

If you add one Magnitude for Size you can increase the volume by x10 or more, but not equal to or exceeding x100. So let's say, a x4.5 increase in linear dimension or a x91 increase in volume. More size modifiers allow greater increases in size.

However, this does not neatly address shrinking the size of an object, since you should be able to shrink the object to any size smaller than it actually is (assuming it is naturally the size of a base Individual) without any modifiers.

Mark