Line of sight for casting

Discussion on game mastering Earthdawn. May contain spoilers; caution is recommended!
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Line of sight for casting

Post by Bonhumm » Fri Sep 13, 2019 10:14 pm

I would like to have your opinions (especially from any DEV) about the following issue and questions:

About 'line of sight' for casting, the Player's states that:
'Any method that makes the magician certain of the target’s location allows the creation of the proper astral arc'

And then goes on giving examples like directly touching the target count as 'certain' even in darkness. And I think it would be logical to assume to other senses might also 'count' like smell or hearing (especially for critters).

Previous discussions about the use of the Wizard spell 'Astral Sense' in relation to 'line of sight' in these forums went on for a long time but I think the consensus was that although the caster 'is certain of the target's location' while sensing someone inside a nearby closed room, he cannot cast spell on him because there is no physical 'arc' between him and the target for the spell to 'fly' through.

I (think) that it was also the consensus that even just standing behind a wall (i.e. NOT in an enclosed area) would prevent a mage using Astral Sense from casting a spell to a person even though an 'arc' is 'available' (right/wrong?)

So, my questions:

1- Could indeed a caster successfully target an (example) ork behind a wall using nothing other than Astral Sense IF the 'ork' is not in an enclosed room (for example, just a standing wall in a castle ruin).

2- What about shadows? If I (clearly) see the shadow of someone standing behind a corner, can I target him for spellcasting?

3- How about reflections? I see somebody's reflection in a mirror standing beside the corner. Targetable or not?

4- Someone is hiding in muddy water; completely invisible to regular sight; would someone using Heat Sight be able to target him?

I would appreciate you take and opinion on those. Thank you again.
Last edited by Bonhumm on Sat Sep 14, 2019 12:29 am, edited 1 time in total.

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Re: Line of sight for casting

Post by Sharkforce » Sat Sep 14, 2019 12:08 am

i'm not a dev, but on your 4th question, presuming you meant heat sight... thermal vision does not generally speaking penetrate solid objects. if you are on one side of a wall, and there is a person on the other side of the wall, you will not see them unless perhaps they've been leaning against the wall long enough for the wall to heat up (and even then, you're not really seeing them, you're seeing the heat on the wall... if they moved away, the heat would gradually fade, but for a little bit at least it would still look like they were there. and that presumes the wall is thin enough for this to all happen in any reasonable amount of time).

in fact, not only does thermal vision not see through stuff like stone or wood irl, it doesn't even necessarily work through materials that are transparent to regular vision; someone could potentially hide behind a sheet of clear glass if all you had to spot them with is thermal vision. you would be able to see the sheet of glass, but again, generally speaking you aren't going to see through it unless something behind it is close enough and has enough temperature difference to heat up (or cool down) that sheet of glass.

so if someone is hiding in muddy water, in the sense that their body is fully inside the water by a reasonable amount, heat vision is not going to do much for you. now, if they're standing in an area with muddy water and their head is out of the water, you'll probably be able to see their head no problem, but submerged, the question is moot because heat sight isn't going to see the target any better than regular vision (and quite possibly much much worse, if we were talking about clear water, since water also generally does an excellent job of blocking thermal vision; you'll see a reflection of other nearby stuff on the surface of the water instead of seeing anything beneath the surface).

now, just to be clear, there are plenty of situations where thermal vision should make someone stand out really obviously when they would be near invisible to regular vision; being a warm-blooded creature makes it especially difficult, as you are the equivalent of a light source, so you really need to go to greater lengths to hide from thermal vision just as you would need to work really hard to hide from regular vision if you were carrying a glowstick in the dark.

all of which is to say: the point is moot, heat vision won't let you see the person anyways :P

(note: this is not true if you were to try coating yourself in mud; that works about as well as coating yourself in clothing. you'll still be plenty visible, although you might look a little weird i guess. coating yourself in mud would leave you quite visible to thermal vision, you'll just heat up the mud in short order... it might work for a few seconds if you were to have a whole bunch of fresh mud dumped on you i guess. basically, what i'm trying to say here is that what arnold does in the first predator movie should not have worked... but then again, it would've been a much crappier movie if he'd just been shot dead and that was the end of it =D )

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Re: Line of sight for casting

Post by Altanius » Sat Sep 14, 2019 8:18 am

Sharkforce wrote:
Sat Sep 14, 2019 12:08 am
i'm not a dev, but on your 4th question, presuming you meant heat sight... thermal vision does not generally speaking penetrate solid objects.
all of which is to say: the point is moot, heat vision won't let you see the person anyways :P
Not to nitpick, but I'm pretty sure he was asking if you could cast a spell on someone you could see with heat sight but not with ordinary vision, not if IR could pick up someone underwater, which would be a discussion for another time.

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