This is a great combination! The rules for casting two spells with a bonus action and action simply state (PHB, 202):
A spell cast with a bonus action is especially swift. You must use a bonus action on your turn to cast the spell, provided that you haven’t already taken a bonus action this turn. You can’t cast another spell during the same turn, ...
You do not need line of sight at all
Spells will tell you the requirements to cast them. All spells require (unless indicated otherwise), a clear path to the target, but line of sight is not a general requirement. In other words, spells only require line of sight if they specifically say so.
Here are the targeting requirements for wall of fire:
A wall of force grants cover by being an obstacle. A confirmed tweet from a game designer states this includes spells.
According to the cover rules in the Player's Handbook, p.196:
Walls, trees, creatures, and other obstacles can provide cover during combat, making a target more difficult to harm. [...] A target has half cover if an obstacle blocks at ...
Being supported does not necessarily mean "supported from below". By Cambridge dictionary it means:
to hold something firmly or carry its weight, especially from below to stop it from falling
Especially, yes, but not exclusively, and because spell explicitly says it does not need to be from the bottom, other sides should be OK.
Stalactites are supported ...
No, it doesn't
It only damages creature on your chosen side (north). The spell description clearly states at the end of the same paragraph that the other side deals no damage at all:
The other side of the wall deals no damage.
The side you chose is the red, not the grey. I can see your confusion arise from interpreting 'side' as the 'surface' of the ...
Yes, that's almost (but not quite) correct.
Creating the wall of fire as a ring means everyone inside is going to take damage, yes. However, it's better than you're thinking, because they don't get any saving throws!
The saving throw is only for anyone in the area of the spell when the wall of fire first appears:
When the wall appears, each creature ...
No, Wall of Force does not block teleportation. The relevant parts of the spell description are:
Nothing can physically pass through the wall.
This is pretty unambiguous, but teleporting isn't "physically passing" through the wall, so that's fine.
The wall also extends into the Ethereal Plane,
blocking ethereal travel through the wall.
This is, ...
Wall of Force provides total cover against Wall of Light
The dome created by Wall of Force provides total cover for anything inside the dome from any effect outside it.1 This means that the point of origin for Wall of Light must be outside the dome, as described in the spell targeting rules:
To target something, you must have a clear path to it, so it ...
If you are speaking of the spell Wall of Water, this case is covered in the description of the spell:
[...] fire damage is halved if the fire effect passes through the wall to reach its target
Yes it would work, but the damage is halved.
In variant A and B, a creature doesn't cast a "shadow" in a spell's area of effect. As you said:
To block one of these imaginary lines, an obstruction must provide total cover
Creatures do not provide total cover; they provide half cover, as described in the Cover rules in the Player's Handbook (p.196):
A target has half cover if an obstacle blocks at ...
Unless the spell text specifies, that is left to a DM ruling.
A question like this highlights how integral to this edition of the game the "rulings > rules" philosophy is in aiding a DM, or a whole table, in resolving such puzzles.
We had an extended discussion about this on the GiTP forums regarding casting Leomund's Tiny Hut on a ship. The consensus ...
Yes, it applies to all (normal) projectiles fired through the wall
As you noted, the wind wall spell creates a wall of wind that blows upward, and says:
Small or smaller flying creatures or objects can't pass through the wall. Loose, lightweight materials brought into the wall fly upward. Arrows, bolts, and other ordinary projectiles launched at targets ...
Wall of Force does not transfer thermal energy.
The Player's Handbook describes the spell as:
immune to all damage
Cold and fire are both types of damage, and in your example we can assume that the lava would cause fire damage.
The question, then is "Can Wall of Force allow damage to pass through it if it does not take damage itself?" The answer still ...
Strict RAW can be read this way but is confusing
One side of the wall, selected by you when you cast this spell, deals 5d8 fire damage to each creature that ends its turn within 10 feet of that side or inside the wall. [...] The other side of the wall deals no damage.
A big part of the issue here is that the phrase "side of the wall" is not well-defined. ...
Yes, it can stop shockwaves
As per Wall of Force's spell description:
Nothing can physically pass through the wall.
Shockwaves are vibrating air, and since air cannot pass through the wall, there is no shockwave that would extend outside it.
As for light, it seems the intention is to allow it to pass through the Wall, my basis is that it doesn't ...
It is reasonable to assume it is immune to thermal energy.
Per the text in the spell.
Nothing can physically pass through the wall.
Which should logically include thermal energy - or more correctly stated - fire damage. If it had said it is immune to physical damage, I would rule differently, but this does not seem to be referencing a keyword. ...
No, the panels must form a single contiguous surface.
The full description of the flat wall form is:
... you can shape a flat surface made up of ten 10-foot-by-10-foot panels. Each panel must be contiguous with another panel.
Because it says "a flat surface", I interpret that to mean that all 10 panels must be connected into a single contiguous surface, ...
Almost any creature could escape before suffocating
In most circumstances, the victim would have ample time to chisel their way out.
Wall of Stone creates 10 foot panels (or larger). So let’s assume: (1) your spellcaster trapped their victim in the minimum size, 10' cube, and (2) they concentrated on the spell for 10 minutes, making the stone permanent.
The spell wall of water is strict in its dimensions
The 4th-level Sor/Wiz spell wall of water [conj] (Spell Compendium 235) is shapeable, which means the caster
can shape the spell. A shaped effect or area can have no dimension smaller than 10 feet. Many effects or areas are given as cubes to make it easy to model irregular shapes. Three-dimensional ...
Yes, area effects will cross through the walls
There is no language in any of the layers, or the general wall itself, that state it acts as cover or that spell effects can't pass through it.
Prismatic Wall is described as(emphasis mine):
A shimmering, multicolored plane of light forms a vertical opaque wall--up to 90 feet long, 30 feet high, and 1 inch ...
Without illusions: passwall
This spell can create a window, plain and simple, although not a very decorative one. It also has a duration and thus can be dispelled (unlike stone shape). You might have to provide a way for the NPC creating it to make it permanent until dispelled, as the duration is only 1 hour. You could place it in a glyph of warding, but ...
Creatures do not move when making a saving throw against wall of fire
The wall of fire spell states:
[...] When the wall appears, each creature within its area must make a Dexterity saving throw. On a failed save, a creature takes 5d8 fire damage, or half as much damage on a successful save [...]
One thing we know is that spells do only what they say ...
You need Line of Effect to "effect" creatures.
This is true for Aura's
The aura fills the creature’s space and each square that is both within a specified distance of the creature and within line of effect of it.
A blast affects a target only if the target is in the blast’s area and if there is line of effect from the origin square to the ...
Yes you can do this
The description for Wall of fire only lists a range and makes no mention of a line of sight requirement:
... RANGE/AREA 120 ft ...
You create a wall of fire on a solid surface within range. You can make the wall up to 60 feet long, 20 feet high, and 1 foot thick ...
Additionally, the wall can be up to 60 feet so even if the ...
Yes, it would block and contain the sound and the shockwave. It won't stop the explosion, but would contain it. The Wall of Force is transparent, so there would be a bright flash. Depending on the size of the explosion, if the Wall of Force was a hemisphere over the top, rather than a sphere with full containment, the explosion and shockwave could still ...
The fireball is blocked
There's a couple things regarding prismatic wall (in sphere shape) that blocks fireball in your situation.
First, the spell cannot target a creature on the inside of the sphere because the caster does not have line of effect (nor line of sight) to that target. So were you to attempt to target someone inside of the sphere, the spell ...
As you've identified, the rules are ambiguous here. It seems to me that the pigments operate by transforming the wall behind them into a nonmagical doorway, and that this transformation is magical and would apply to a wall of force just as effectively as a nonmagical wall.
But you might also argue that the wall of force is a nonphysical object, or that ...
Yes, because other illusions can do similar things
I am not sure if there is a printed spell which will do this, but I would say it is possible. My reasoning is that other spells can do similar things. What you want to do here is to allow vision through an object. Disguise self allows you to appear a foot shorter, so it must allow vision through your head ...
This is explicitly supported by the spell.
First, note that it cannot be a dome because it has to be square panels:
The wall is 6 inches thick and is composed of ten 10-foot-by-10-foot panels. Each panel must be contiguous with at least one other panel.
Still, it's possible to trap creatures using this spell. The spell acknowledges this possibility, and ...
Yes, this should work. You'd cast Wall of Water in such a way that the creature is inside the wall. Then you'd cast Ray of Frost on that creature, freezing the 5-foot square section around it (which is 1 foot thick).
From the Wall of Water spell description:
Spells that deal cold damage that pass through the wall cause the area of the wall they pass ...