Detecting spirits without intellego

[Berengar]

@raccoonmask

By the Founders... there's a thing we've missed...

There's been a certain level of argument and confusion back and forth. And I've even been a part of it. This time I did even more reading and research, and I found the following insert in the main book:

@ArM5 p113

The target of a Creo spell that actually creates something is the thing created. The target is thus always Individual or Group. A spell to create a part of something is either a healing spell or a Muto spell, depending on the part created. A Creo spell with target Room cannot be used to fill a room with something. Instead, use target Group with an appropriate size modifier.
The Creo guidelines for each Form give the level required to create different kinds of thing. The size is determined using the standard rules for target size

To get things back on track and away from the manifold 'tangents' that crop up: You did not care about CrIm or MuIm in

@"raccoonmask [url=https://forum.atlas-games.com/t/card-board-games-archive-links/116/1

here[/url]"]Translating this to our current discussion, let's assume instead of intangible tunnels, we're playing with demons again. A room-wide Perdo Vim can damage all the demons in a room. Can a room-wide Creo Imaginem paint all the demons mauve? Dear magic, please make all the demons in this room illuminate with hideous color, thanks magic. Like a computer, magic isn't thinking for itself, its carrying out its instructions. You say paint the demons, it pulls out a list of demons in the room from your head, finds none, 404.

Neither did I care for it in my direct answer here nor Ovarwa in his answer to that. So I correct my answer to raccoonmask to

@One Shot

Here's a sketch of the structure of the problem, what a T: Room spell can affect and distinguish. I hope it helps.

@ArM5 p.13 (underscore mine)

Room: The spell affects everything within a chamber. ...

This suggests, that the main differentiation is its basic spell parameters: Technique, Form, Guideline.

• Cast a T: Room DEO? Then you would affect everything and everybody in the room, but as DEOs by their general PeVi guideline, their explanation in ArM5 p.160 (plus LoH p.12f Research and such) affect only demons, this takes then only effect on demons, and might not even challenge the Parma of a magus also present in the room.
• Cast a T: Room MuIm spell magically painting everything in the room in specific Tartan colors? Then everything and everybody in the room gets painted, but for resisting beings and those entities like ghosts, demons and exits of Arcane Tunnels which have no shape to paint on.

This is just a rough approach. From it, the storyguide needs to determine what in the room each T: Room spell by its general parameters can and cannot affect. But magi inventing or sponting T: Room spells and effects to be more specific in what they wish to affect would have to resort to ArM5 p.114 Requisites to make the distinctions, thereby typically adding magnitudes for Intellego. Often using a T: Group instead would be more helpful: but

@ArM5 p.13

The components of the group must be close together in space, and the group itself must be separated from any other things of the same type

, so the caster must be able to identify the group when casting.

Cheers