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Maginomicon
2013-08-14, 12:56 PM
I have a house rule that was originally intended to answer the conundrum of fighting through glass and other barriers that allow line-of-sight but not "traditional" line-of-effect. I quote it below for context.

Do not respond to this thread with statements of whether the house rule is rules-legal. It's a house rule, so its intention is to FIX something in the RAW that doesn't make logical sense. If you disagree, I defer you to the last line of my sig.


Line-of-Effect vs Line-of-Sight

In situations where you have line-of-sight but not necessarily true line-of-effect (such as when looking through a glass window or shutter), generally use the description of the effect to determine whether you need mechanical (“true”) line-of-effect.

The following new terms categorize certain kinds of effects:

“Grenade-like”: Some kind of object is hurled or fired at a destination (which is usually a square), auto-hits the destination, and then has an area-of-effect centered there (i.e. Fireball, Hail of Crystals, etc.). This category includes cones centered at the user (colloquially called a “shotgun-like” effect).
“Ray-like”: Some kind of object (usually a visual ray) is hurled or fired at a destination (which could be a square) as a ranged touch attack. (i.e. Scorching Ray, Crystal Shard, etc.)
“Bullet-like”: Some kind of object is hurled or fired at a destination (which could be a square) as a ranged attack (not a ranged touch attack). (i.e. Giant’s Wrath, Invisible Needle, etc.)


Effects that do not describe a grenade-like, bullet-like, or ray-like means to get from you to their destination do not require true line-of-effect and only need line-of-sight (even if that line-of-sight is through a glass window, a screen, or scry). However, the physical destination of the effect must still be within the effect’s stated physical range (“range+radius” for some area effects) ignoring obstacles (Yes, this means you’ll often have to look up the flavor text for each effect if it’s from the SRD/OGC, but that’s nothing new). If this puzzles you, you can think of it as “the influence of your magic does not spread beyond the physical range of the spell”.

Use your best judgement on what grenade-like, bullet-like, or ray-like effects do to intervening obstacles (such as whether they count as “soft cover” or whether it’ll damage, destroy, or move the obstacle in some way).

Realize that a lot of psionic powers do not mention any sort of need for a true line-of-effect. Additionally, the psionic character could “dispense with displays” (and generally will always attempt to anyway since there’s no negative cost for failure) to completely remove that display. However, if the power’s description directly describes a grenade-like, bullet-like, or ray-like effect as a means for the power to get from the manifester to the destination, then the dispense with display option will not dispense with that aspect of the display (and thus, still requires true line-of-effect).

For portal-like effects, the squares on one end of the portal are considered adjacent to the squares on the other end of the portal for the purposes of line-of-effect and line-of-sight (unless stated otherwise). This particular rule ignores the limits on interplanar range such as written in the clairvoyance spell (the portal has to at least be within range of the clairvoyance spell). Effects which attempt to cross planes use the location of the nearest physical connection between those two planes (such as a portal) when determining if something is within the stated physical range.

Mirrors, Visual Rays, and Light

If an effect is visually a ray (ex. “Scorching Ray”) and such an effect is aimed at a mirror or other reasonably reflective surface of any kind, the ray bounces off of the mirror as appropriate. Likewise, if the effect is a light effect (such as having the “light” descriptor), it should also bounce off of all mirrors as appropriate. In either case, be sure to consider the angle of incidence to the mirror so far as whether it can hit something reflected in the mirror.

Only the reflectiveness of the reflective surface (i.e. “is the mirror cloudy” or “how still is the water”) should determine whether there are any detriments to the effect or penalties to its chance to hit something after the reflection. GMs should use their best discretion on how reflective a surface is, but generally if a player has direct control over the reflectiveness of the surface somehow (such as personally creating the reflective surface through the “Mirror” or “Create Water” spell) then they should determine how reflective the surface is (initially, in the case of “Create Water”).

What I want to know is:


How would these house rules as-stated affect DMM/Persist shenanigans? (using Ocular Spell, Reach Spell, etc.)
How would these house rules as-stated affect other notable relevant shenanigans?
What do these house rules "break"? (i.e. make no longer work as intended or make pointless)
How could these house rules be abused by optimization? (House RAI is more important than House RAW here)
How can I make the ambiguity of "reflectiveness" more clear?


P.S.
The Mirror spell is in Dragon Magazine #302 page 50, and creates an illusory 1 sq.ft. one-way mirror that floats in space and can be reshaped or repositioned.

Fax Celestis
2013-08-14, 01:32 PM
Look fine to me.

Grenade-likes (mainly bursts like fireball, but also lines like lightning bolt and cylinders like flame strike), by the way, are not centered on a square, but on an intersection.

Lapak
2013-08-14, 02:33 PM
First thing that occurs to me is to wonder whether this also applies to invisible force effects - since we're already in house rules territory, it feels off to me if a Wall of Force is so permeable to magic just because it's clear. I don't have any problem with casting Charm Monster or whatever through glass, but casting through a force effect somehow seems off.

Not to mention that it makes Forcecaging oneself or the like an even more potent tool for wizards, who can now block themselves into an indestructible fortress (except to other casters) yet still shoot OUT.

Chronos
2013-08-14, 03:19 PM
The first thing that strikes me about the "glass window rule" is that it helps casters, but doesn't do anything for noncasters. I'm always reluctant to use any houserule that increases the caster-noncaster discrepancy.

The mirror rule, I don't have any actual problem with, but it seems like it could be a pain to resolve. Basically, if a player wanted to try to pull it off, I'd let him (and also let him do all of the calculating and plotting needed), but I wouldn't bring it up otherwise.

Urpriest
2013-08-14, 04:22 PM
What I want to know is:


How would these house rules as-stated affect DMM/Persist shenanigans? (using Ocular Spell, Reach Spell, etc.)
How would these house rules as-stated affect other notable relevant shenanigans?
What do these house rules "break"? (i.e. make no longer work as intended or make pointless)
How could these house rules be abused by optimization? (House RAI is more important than House RAW here)
How can I make the ambiguity of "reflectiveness" more clear?


P.S.
The Mirror spell is in Dragon Magazine #302 page 50, and creates an illusory 1 sq.ft. one-way mirror that floats in space and can be reshaped or repositioned.

I don't think it affects Persistomancy shenanigans at all...I guess maybe it allows buffs to be cast through scrying sensors? Beyond that though, looks like it leaves that part of the rules the same.

Raimun
2013-08-14, 06:58 PM
Hmm... this still calls for a lot of judgement.

For example:

A Fireball should detonate on impact, ie. when it hits the glass. However, people near the window might still be hit.

A lightning bolt (etc. line) would just go through the window... unless it's some kind of uber-bullet proof-kind of glass in which case it would need to be able to break through the window with its damage, if it is to damage someone standing behind the window.

I still think a window would protect against rays perfectly. Ray of Enfeeblement would just "enfeeble" the window, ie. the ray is wasted. The window would also protect against Disintegrate but only once, since there would be no window after it's taken one hit.

Duke of Urrel
2013-08-14, 08:21 PM
It may be possible to simplify your rules, Maginomicon. You have described three categories of spells (and other magical phenomena, such as magic-item functions and supernatural effects) that require true line-of-effect: grenade-like, bullet-like, and ray-like. Wouldn't it be simpler to create a single category for spells that don't require true line-of-effect, but only line-of-sight? This category would include those spells (and other magical phenomena) that work because they can be seen, such as gaze effects, visible illusions, effects of bright light, etc. These are also the effects most likely to bounce off of mirrors.

On the other hand, I think several different kinds of objects may be barriers to line-of-effect, and they should be treated differently. For example, the descriptions of the Fireball spell and the Lightning Bolt spell allow them to break through solid barriers, including glass windows and thin walls of ice, but these two different substances may respond differently to these spells.

I agree with Chronos that we shouldn't give spellcasters any more advantages over non-spellcasters if we can avoid it. I am therefore intrigued by the possibility of spell reflection by means of mirrors, which may not always work to the advantage of spellcasters!

Maginomicon
2013-08-14, 09:57 PM
It may be possible to simplify your rules, Maginomicon. You have described three categories of spells (and other magical phenomena, such as magic-item functions and supernatural effects) that require true line-of-effect: grenade-like, bullet-like, and ray-like. Wouldn't it be simpler to create a single category for spells that don't require true line-of-effect, but only line-of-sight? This category would include those spells (and other magical phenomena) that work because they can be seen, such as gaze effects, visible illusions, effects of bright light, etc. These are also the effects most likely to bounce off of mirrors.Those three categories are used elsewhere in my house rules (and in my campaign setting document) to distinguish them in other ways than whether they require line-of-effect. They're also distinguished so that it's easier to convey a type of effect that fits them. For example, a "ranged attack" could ambiguously refer to just "non-touch" ranged attacks or both "touch" and "non-touch" ranged attacks. Being able to say "it's bullet-like" or "it's ray-like" make it more clear in common language what's going on (at the very least in fluff).

On the other hand, I think several different kinds of objects may be barriers to line-of-effect, and they should be treated differently. For example, the descriptions of the Fireball spell and the Lightning Bolt spell allow them to break through solid barriers, including glass windows and thin walls of ice, but these two different substances may respond differently to these spells.I did mention that the GM should "Use your best judgement on what grenade-like, bullet-like, or ray-like effects do to intervening obstacles (such as whether they count as “soft cover” or whether it’ll damage, destroy, or move the obstacle in some way)."

I agree with Chronos that we shouldn't give spellcasters any more advantages over non-spellcasters if we can avoid it. I am therefore intrigued by the possibility of spell reflection by means of mirrors, which may not always work to the advantage of spellcasters!
Having a mirror (either as a spell or as a mundane ordinary mirror) change up combat was actually part of the point. Mirrored shields are also an option. If the ray would miss because of the shield AC (in this case, shield AC would count against the ranged touch attack) or an action was readied with a mirrored shield to explicitly do so (or they took a total defense action, although that provides a dodge bonus), the defender might get a choice to reflect the ray at something (as the Rogue ACF). That actually makes casters less powerful because it means that there's now a common mundane defense against rays and [light] spells.

Chronos
2013-08-14, 10:10 PM
I like the idea of mirrored shields, but this:

If the ray would miss because of the shield AC...
is difficult to adjucate. Let's say that you have +2 deflection, +2 dodge, and +2 shield to your AC (total AC of 16), and an attacker rolls 15 to hit with a reflectable ray. You could say that without the shield your AC would be 14, and so you would have been hit were it not for the shield, and thus the ray misses "because of the shield AC". But by the same token, you could also say that the ray would have hit were it not for the dodge bonus, and so the ray missed "because of the dodge AC". Or likewise, it missed "because of the deflection AC".

Maginomicon
2013-08-14, 10:23 PM
I like the idea of mirrored shields, but this:

is difficult to adjucate. Let's say that you have +2 deflection, +2 dodge, and +2 shield to your AC (total AC of 16), and an attacker rolls 15 to hit with a reflectable ray. You could say that without the shield your AC would be 14, and so you would have been hit were it not for the shield, and thus the ray misses "because of the shield AC". But by the same token, you could also say that the ray would have hit were it not for the dodge bonus, and so the ray missed "because of the dodge AC". Or likewise, it missed "because of the deflection AC".
Not really. (http://www.giantitp.com/forums/showthread.php?t=293895)

Fax Celestis
2013-08-14, 10:48 PM
Not really. (http://www.giantitp.com/forums/showthread.php?t=293895)

The issue with this is that it makes low-armor-high-dex characters (like, say, a rogue or a monk) have a smaller 'deflection window' than a low-dex-high-armor character (like a knight or paladin). I have had a few characters whose touch AC was higher than their regular AC (due mostly to shenanigans, but still), which would mean I couldn't deflect at all.

Maginomicon
2013-08-14, 11:19 PM
The issue with this is that it makes low-armor-high-dex characters (like, say, a rogue or a monk) have a smaller 'deflection window' than a low-dex-high-armor character (like a knight or paladin). I have had a few characters whose touch AC was higher than their regular AC (due mostly to shenanigans, but still), which would mean I couldn't deflect at all.
Doesn't that actually make logical sense? Didn't Link to the Past get much more awesome fluff-wise (although a bit late) once you got that ginormous mirrored tower shield?

Also, you might be misunderstanding me. Mirrored shields would simply be a small add-on cost (or perhaps an inherent part of any masterwork cost) to metal shields which says "This shield may apply its shield bonus against touch attacks caused by rays and [light] effects. Further, if the touch attack would miss if not for the shield bonus, blah blah blah etc."

Plus, that gives more armor-oriented characters (like a knight or paladin) a thematically-reasonable leg up on casters anyway, so... win-win.

Fax Celestis
2013-08-15, 12:21 AM
I could be okay with it if you were to roll in a bonus to that range into Combat Reflexes.

Chronos
2013-08-15, 08:50 AM
I don't have any objection at all to mirrored shields on grounds of coolness. I'm just saying that a lot of people think they know what they mean by "if the touch attack would miss if not for the shield bonus...", when they actually don't.

erikun
2013-08-15, 09:12 AM
The biggest problem I see with this idea is what happens with scrying and other such divinations. You have Line-of-Sight to objects within range of a Scry spell, but clearly not Line-of-Effect. With this ruling, it would be possible to cast Dominate Person, Forcecage, or just slap down Wall of Stone wherever you want.

Even when you're limited by range, it's still possible to use Clairvoyance to look through walls and cast spells on creatures on the other side.

Maginomicon
2013-08-15, 09:23 AM
The biggest problem I see with this idea is what happens with scrying and other such divinations. You have Line-of-Sight to objects within range of a Scry spell, but clearly not Line-of-Effect. With this ruling, it would be possible to cast Dominate Person, Forcecage, or just slap down Wall of Stone wherever you want.

Even when you're limited by range, it's still possible to use Clairvoyance to look through walls and cast spells on creatures on the other side.

That's exactly the point. Spell range seems to never really come into play (at least in my group). Having a reason for spell range and Enlarge Spell to come into play more often is nice. Further, I see nothing wrong balance-wise with letting people cast non-L-o-E spells on creatures or locations through a scry with that crippling limitation.

<Fighter> Where the f*** did that fiendish rhino come from?
<Rogue> The evil wizard whose bedroom door we're just outside of must know we're here! Run!
<Evil_Wizard> Hehehehe~ You fools!