Pinning down Weaving for more consistent rulings

[Mrmdubois]

Mass and density both seem like properties you could alter relatively easily at 3 dots.

Something that might be helpful to keep in mind is that Weaving happens at the same point as getting Perfecting and Fraying. If you could Perfect or Fray a part of your subject, then you can also Weave it into something else.

[galivet]

It may seem ludicrous, but honestly I would allow it as a Space Weaving spell. It's not dissimilar from Ban.
Edit: But do note that "elevation above sea level" is an arbitrary measurement and not a proper quality. The spell would instead change the distance between two points within an AoE. For elevation, the points would be the sea level somewhere below ground, and the ground, but it's probably much more effective between two horizontal points where the practical effect would be similar to Ground-Eater.

Yeah, if "elevation" is considered a property of an object for which Weaving can modify the value, then we may as well say that "position" overall works the same way so we can accomplish teleportation with Weaving. Obviously that's somehow untrue since Teleportation is a Patterning spell, but I can't explain why. The restriction on Weaving is that the target can't be completely transformed. Teleportation doesn't completely transform the target; it modifies the target's location property. Or, if I'm misunderstanding that, it's not clear how "location" is not valid as the property of a subject of a spell.

So it's unclear to me how to know what things we commonly think of as "properties" are actually something more fundamental that requires Patterning to change.

After reviewing the published spells several times trying to work up my own heuristics, the best I came up with is balance concerns: some spells arbitrarily require higher practices, mana, etc... just because they're particularly useful and since that's a subjective call you can't apply consistent judgement about it for Creative Thaumaturgy. It's like holdover 1e thinking.

[galivet]

How about physical properties like mass and density in the context of Matter and Life?

Possibly there are some properties that don't fall under any specific Arcanum and in those cases you consider only the appropriate Arcanum for the target?

[Tessie]

I'll also say that "property" itself is ambiguous.

"Elevation above sea level" is a property that everything has, even spaces. Modifying that directly seems ludicrous, but why? There is some heuristic in play there that I can't articulate.

It may seem ludicrous, but honestly I would allow it as a Space Weaving spell. It's not dissimilar from Ban.
Edit: But do note that "elevation above sea level" is an arbitrary measurement and not a proper quality. The spell would instead change the distance between two points within an AoE. For elevation, the points would be the sea level somewhere below ground, and the ground, but it's probably much more effective between two horizontal points where the practical effect would be similar to Ground-Eater.

[galivet]

EDIT: Never mind, I misread.

[galivet]

I'll also say that "property" itself is ambiguous.

"Elevation above sea level" is a property that everything has, even spaces. Modifying that directly seems ludicrous, but why? There is some heuristic in play there that I can't articulate.

[Tessie]

Left unstated is whether the Arcanum of the spell must govern the modified property, the nature of the modification to the property,

If these can't be attributed to the same Arcanum, you're probably transforming the property rather than modifying it, making it a Patterning spell.

But if you do modify a quality in a way where the chosen Arcanum doesn't govern both of these, you need to add another Arcanum. For example, State Change changes the property of the subject's state of matter, but one of the four fundamental states does not fall under Matter so you need to add Forces to change the subject's state to plasma.

the target itself,

The target should only be needed to be governed by the Arcanum if the nature of the target is the focus of the spell, which, again, would probably make it a Patterning spell rather than Weaving. Unfortunately there are tons of exceptions, generally involving Forces, Life and/or Matter.

Also left open to interpretation is what qualifies as a "completely different." I suppose these are two points for which I would like some additional heuristics.

I feel the ambiguity opens me up to making inconsistent and even biased rulings during game play.

The best way seems to be to just familiarise yourself with the published spells to get a feeling for it. Personally I tend to think of Weaving as "modification" and Patterning as "transformation" and work from there, but that does not follow the published spells as closely as I'd like.

[galivet]

For me, the RAW constraints on Weaving spells are too vague. I believe that there are some implied restrictions or other heuristics in play when determining whether a Weaving spells is valid, and I would like your opinions on those.

Here are the explicitly-stated restrictions:

1. The spell modifies nearly any property of the target.
2. The spell must not transform the target into something completely different.

Left unstated is whether the Arcanum of the spell must govern the modified property, the nature of the modification to the property, the target itself, or some combination(s) of those. Also left open to interpretation is what qualifies as a "completely different." I suppose these are two points for which I would like some additional heuristics.

I feel the ambiguity opens me up to making inconsistent and even biased rulings during game play.