The base individual of Terram - Plastics and Minecraftians

Recently I was designing a spell and came upon an interesting dilemme about how to interpret the base individual of Terram.

The spell in question is important so here it is, for purposes of understanding the dilemma:

The engravers relief
ReTe 10
Range: Touch, Duration: Mom, Target: Part.
This spell creates a relief or engraving upon the surface of a stone. This spell is a craft magic spell, as it does the same work as could be done by a mundane stonecarver/engraver. The result of the spell is the creation of a Bas-relief upon the surface of a stone.
Base 2 (from covenants p. 51), +1 touch, +2 part, +1 stone)

The question is: How big a relief can this spell create?
The naive answer to this question is "a base individual of stone".
Th problem with the naive answer arises because the spell has an effect that is mostly two-dimensional with a Target of "Part", but the base individual is three dimensional. So how does the 3D invidiual transform down into 2D?
Note: The choice of target is because I want to cast the spell on larger rock formations to create engravings, e.g. on mountainsides, inside caves, etc.

I have come up with two possible interpretations, which I call the "platic position" and the "Minecraftian position" respectively.

The plastic position is that the spell can affect one cubic pace's worth of stone, but that this cubic pace can stretch, such that the maximum amount of relief creates is equal to the maximum depth of the relief multiplied by the surface area of stone covered by the relief.

The minecraftian position is that the spell can extend over the surface of a cube 1 pace on each side and to a depth of as much as one pace. This happens because the spell is T:Part, and the part is interpreted to be 1, minecraft style block of stone in the larger mass of stone that the part belongs to.

There is a sort "sub-position" to the minecraft position, which states that the spell affects a sphere with a volume of 1 cubic-pace.

Which position do the rest of you favour and why? Perhaps a different one entirely?

I design my spell with the plastic equivalent. For things like Rego and Muto Terram that uses Part, the less depth the spell has, the more width it can have - it's a tradeoff. For ease of calculation, I tend to convert cubic paces into 27 cubic foot since a cubic pace is rarely a convenient measuring unit. In a case like this, however, you do want a fair amount of depth - perhaps not a pace of depth, but you probably want at least 6 inch to a foot, otherwise you'll lose a lot of potential.

I think that both the Plastic or Minecraft interpretations are legitimate, the plastic one is more lenient as it allows for more flexible casting. I think that I prefer the Minecraftian one, where the cube is a pace per side, which translates to digging a square of 1 pace per side to a depth of one's choosing.
The plastic interpretation gets a bit silly, as carving just 1 inch deep mean carving a huge fresco at once (18 paces by 2 paces high at a depth of 1 inch, for example).

Ultimately, I'd say that it is up to the saga and so long as consistency is maintained, both are fine.

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I dislike the plastic position as it seems too open for weird interpretations and exploits that don't fit the setting.

A magi gets a cubic foot of stone, and then shapes it a tenth of an inch wide and a tenth of an inch deep, allowing it's length to be nearly 3 miles. Anything with a 3 mile range should have size mods.

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So, that fresco of yours, 54 foot large by 6 foot high, how long would it take a mundane craftsmen to carve from rock? Did I hear you say a year to carve? What's the difficulty of the check for the mundane craftsmen? If you're looking at a Finesse check with Difficulty 21, you can say whatever you want, I don't think having to raise your Finesse skill to 15 to use that spell to do something beautiful can be called lenient. Even carving a simple "Welcome" on the ground will take a fair level of Finesse.

And Lee, the plastic interpretation is consistent with canon spells. For example, Creation of the Walls of Simple Cottage breaks the cubic pace as a basic unit to recaculate the volume in cubic footage since the walls are only 1 foot thick, so does a Network Reminiscent of Rome which creates half-a-pace thick roads. Of course, I don't think anyone will argue against that a 1 inch thick x 1 inch thick x 3 miles long requires extra magnitude, I just don't think it's accurate to call them size magnitude, but complexity, sure. Not that I'm sure I see the use of carving a line like that, except for perhaps a large circle where I'm crossing my fingers not to botch because someone crossed it while I was walking arround and casting.


1st, a bas relief or engraving is likely to range from 1/2 inch in depth to at max two inches. Using two inches for calculation seems reasonable to me- 1/6 of a foot or 1/18 of a pace (roughly), so 18 square paces.
as to the time it would take a mundane craftsman this depends on what is carved and level of detail, which is a question for the finesse roll.

Given that Individual targets are generally plastic, I'd say Part is also plastic.

That is to say, so long as an (Individual) statue has less than a cubic pace of stone in volume, you can affect the statue even if some of its dimensions extend outside of a platonic cube of one pace to a side.

I'd say to use plastic, but to consider not the size of the engraving, but the size of the underlying individual.

Which makes sense: you are affecting a part of that individual.

Yeah, I think the Size should be that of the individual that the Part is a part of. So if you want to engrave a stone that's 100 cubic paces in size, you need +2 size modifiers

What are you talking about?

The Target:Part is explicitly in the game so that you dont have to design spells big enough to affect the entire individual, but can instead settle for part of it.

By that argument it ought to be basically impossible to leave small magical engravings on the surface of a mountain.


You can use the spell on a rock that broken off the mountain. And yes, casting spells on a mountain shouldn't be a trivial thing.

It depends on the spell. For example pit of the gaping earth does not have to affect the entirety of France if cast in a field. Saying it has to be able to affect the entire thing flies in the face of a lot of well established aspects of the game, especially when it comes to Te spells. Size is scaled to the portion which is actually affected, you don't need a spell that can transform a mountain to put your initials on the peak.


What you are calling the "Plastic Position" is the default that the system is built on. The Target gives you how much volume of material the spell creates/changes/controls/destroys, not the shape of which is part of the spell description. Otherwise identical spells by RDT vary only in the description of the shape. In most cases the shape has little to no variation between casting of the spell. Exceptions to this are done by adding Complexity or requiring a Finesse roll.

As for Target Part, where in the description of it (AM5, p.112) did you get the idea it was 2D?

This target refers to spatial parts, parts that you could, at least in theory, cut off and put in a bag.

Spatial things are 3D. Examples like the Arm and Heart being affected by Target Part while they are part of a whole person.

Then we look at the total Size affected by Target Part (AM5, p.113) and find this.

A Part targeted by a spell can be up to the size of the base Individual. Again, every five levels added increases the size that can be affected by a factor of ten. Note that a spell to affect an Individual is five levels lower than a spell to affect a Part of the same size.

So by RAW Target Part is a 3D object, a specific portion of a larger whole, of which that portion can be up to one Base Individual in Size without adding additional Size modifiers. The total size of the object that the Part is part of has no bearing.

It is my spell that is 2D, since it only works on a surface. I know that it is not really 2D since it has depth, but the question in the OP, then is how to model the "cost" of that depth.

The spell is 2D in the sense that for the person using it, the relevant question isnt "how many cubic meters of stone can i use this on?" but rather how many square meters of relief can I make?".

A question which you answered by taking the plastic position.

As for this we absolutely agree, but more than that. I would venture that the core rulebook is sufficiently clear on this matter that it is meaningless to even talk about agreeement or disagreement. It is simply the case.


I feel the plastic position is in line with the general guidelines.

As an aside, we found the target Part concept sometimes confusing and counterintuitive in various ways (e.g., should it be easier to transform a man into a dog, or only his head into a dog's head? It feels like they should both be difficult in different ways, rather than changing the head alone being easier). Consequently, we eventually house-ruled it away. Now, when someone wants to target a part of something, it's treated as an individual of the same size as the part for spell magnitude, but a Finesse test is required depending on how precise an area you want to affect, with failure meaning you affect the wrong part or the spell fails completely. That means some magi are better at targeting a part of something than others. In place of Part we have "Pair of individuals" for each form.

Plastic. As said by many others, the guidelines assume plastic, not only for Terram, but for anything amorphous (the four elements in particular conform strongly to this).

"Sense the Feet that Tread the Earth" is the closest example to a "2D" spell in the guidelines, AFAIK. You feel what is moving on the earth in a 1 mile radius. The spell has +3 Size (10,000 cubic paces). So, the only way for the spell to work is for it to target a thin layer of earth, 1.23 millimeters thick.

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And I think that's the key thing to go with. My fears about abuse is not unreasonable. A munchkin could design a spell working on monofilament size to abuse the rules.

The above spell makes sense and isn't an overpowered exploit. So I'll modify my thinking a little, in that plastic works, assuming spells are designed to the spirit of the plastic principle, not the letter of the plastic principle.

Target Part is not easier than Individual by RAW, except in highly uncommon conditions (generally that would be spells with lots of Size modifier). Most of the time it will be a Magnitude higher. Your example of changing a man into a dog vs changing a mans head into a dog is backwards, since by RAW changing just the head is a Magnitude higher.

Lee, I don't think things get overpowered even if you go to monofilament. To expound based on your previous example:

First, Intellego is less bound than other Techniques with regards to unsensed things, that's why Sense the Feet that Tread the Earth works. How is the magus detecting the whole of this 3 mile X 1 inch X 0.1 inch block of earth? If he isn't, it is debatable if he can use any Technique except for Intellego on such an object.

Let's assume he is, for some particular case, capable of doing it (say, R:Sight on a prairie, nothing else around). It is still earth. A CrTe 3-mile pole will break under its own weight. Mundane earth assuming this shape through Rego would have a higher magnitude (it's something very, very, very unnatural) and keep in mind that it is no more resistant than a twig. PeTe to create a 3-mile long, 1 inch wide, 1/10 inch deep ravine... is no ravine at all. Possible, sure, but useless.

This reasoning can be extended for smaller width and depth (and greater lengths) as far as you are comfortable... which for me would be the moment we start talking modern chemistry. If you require the concept of molecules and atoms to describe something, then hermetic magic isn't capable of doing it.

It is possible that a few abusive cases exist, but I think they are going to be few. As you said, as long as the spell design follows the spirit of the definition (or rather, the spirit of hermetic magic, including all of it's limits) there should be no problem.

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Good point! It's been so long since we changed it I'd forgotten which way round it was.