D&D General "that you can see", "line of sight", glass, mirrors, ~clairvoyance, blindsight, and anything else.

[MerricB]

If you want to see some strange interactions that don't work like you expect, try casting spells through a 5E Wall of Force.

Cheers,
Merric

 

[Paul Farquhar]

5E just calls it an obstacle.

And an obstacle need not be solid. For example, if you are going to rule that radiant damage spells, such as Guiding Bolt, can pass through glass, then you should also rule that it is obstructed by a fog cloud.

 

[Oofta]

And an obstacle need not be solid. For example, if you are going to rule that radiant damage spells, such as Guiding Bolt, can pass through glass, then you should also rule that it is obstructed by a fog cloud.

That's ... just not the way it works. Fog cloud is not an obstacle, the only thing it stops is light waves. Light does not define what an obstacle is.

 

[greg kaye]

... Fog cloud is not an obstacle, ...

It's worse than some obstacles. In some circumstances, obstacles may at least leave you with visual information regarding where opponents (and allies) are positioned as you make your AoE castings.
With fog cloud, you may have even less idea with regard to the placement of AoEs while lack of vision prevents the use of spells needing visual targeting.

 

[Oofta]

It's worse than some obstacles. In some circumstances, obstacles may at least leave you with visual information regarding where opponents (and allies) are positioned as you make your AoE castings.
With fog cloud, you may have even less idea with regard to the placement of AoEs while lack of vision prevents the use of spells needing visual targeting.

It doesn't matter if you can see a target or not, nothing stops a physical object (or magic in D&D) from penetrating the fog. I can fire an arrow at someone in the fog, the odds of my hitting may be low but nothing stops the arrow.

Meanwhile people are arguing that a wall of force that will stop a tank is not really an obstruction because light, and light alone, passes through it. Do what you want, I think the rule is as clear as it will get.

 

[Paul Farquhar]

That's ... just not the way it works. Fog cloud is not an obstacle, the only thing it stops is light waves. Light does not define what an obstacle is.

Sure it is. an obstacle is defined as "a thing that blocks one's way or prevents or hinders progress". A fog cloud blocks or hinders light. It is, therefore, by definition, an obstacle to light.

I can fire an arrow at someone in the fog, the odds of my hitting may be low but nothing stops the arrow.

Sure you can, because a fog cloud is not an obstacle to arrows. But a laser won't pass through it.

 

[Oofta]

Sure it is. an obstacle is defined as "a thing that blocks one's way or prevents or hinders progress". A fog cloud blocks or hinders light. It is, therefore, by definition, an obstacle to light.

Sure you can, because a fog cloud is not an obstacle to arrows. But a laser won't pass through it.

I'm not arguing about this any more. I think the rule is clear, much like my window which happens to be a transparent object made of glass.

 

[Paul Farquhar]

I'm not arguing about this any more. I think the rule is clear, much like my window which happens to be a transparent object made of glass.

It's transparent to visible light, but glass is not transparent to ultraviolet rays.

 

[Oofta]

It's transparent to visible light, but glass is not transparent to ultraviolet rays.
View attachment 286629

Much like a brick wall is transparent to a different wave-length of light, x-rays. Glass is a solid object and stops spells as far as I am concerned.

 

[Deset Gled]

3.5e rules are a bloated legalistic nightmare that produce results that make no narrative sense.

It's transparent to visible light, but glass is not transparent to ultraviolet rays.
View attachment 286629

The 3.5e rules may not be perfect, but generally make more narrative sense than the use of wavelength transmission tables.