Does this errata allow vision out of an area of Darkness?

I thought this was a moot point, settled and done, but a recent errata opens up the question for me again.

Vision and Light (p. 183). A heavily obscured area doesn’t blind you, but you are effectively blinded when you try to see something obscured by it.

This corrects the following rule:

A heavily obscured area–such as darkness, opaque fog, or dense foliage–blocks vision entirely. A creature effectively suffers from the blinded condition (see appendix PH-A) when trying to see something in that area.

Now, this errata implies to me that being within a heavily obscured area does not prevent one from seeing OUT of the area, merely from seeing INTO the area. For instance, a rogue in an area of deep shadow would be heavily obscured to the guard standing by the streetlamp, but the rogue could easily see the guard. (Substitute thick foliage and elf for a less light based situation.)
On the other hand, the rogue would be effectively blinded to anything else in the same area of darkness.

So, what in the Darkness spell specifically prevents one from seeing OUT? The only indication I can see is that “A creature with darkvision can’t see THROUGH” it and that doesn’t really convince me. Can Darkness be interpreted as simply a mobile, impenetrable shadow?

Extended Vision changes ranged effects modifiers due to distance?

I’m trying to build a character that has an incredible vision, using her Extended Senses (Vision). She uses firearms in battle. I kinda wanted to simulate her efficiency in shooting at great distances at easy, but I got stuck in some rules.

Range attacks have three types of ranges: short, medium and long, each one giving different modifiers base on the distance to hit the target.

A ranged effect has a short range of (rank x 25 feet), a medium range of (rank x 50 feet) and a long range of (rank x 100 feet). Ranged attack checks at medium range suffer a –2 circumstance penalty, while ranged attacks at long range suffer a –5 circumstance penalty.

Extended Vision would be a reasonable choice, but it seems to just affect Perception checks and not range attacks. I could use Extended Distance Extra, but it seems that I would need to apply it to each weapon, or at least for a container of powers. Shouldn’t Extended Vision affect the range for ranged attacks?

How does Ring of X-Ray Vision interact with Illusion spells and similar effects?

Specifically, the ring states that “solid Objects within that radius appear transparent and don’t prevent light from passing through them”. Does it apply to solid objects created through illusion?

It seems unlikely that the ring works selectively, and illusions can’t plausibly “know” they are being viewed in that way.

By extension, the Ring of X-Ray Vision seems to allow its wearer to inspect the internal organs of a person (be it through selective sight if we consider it to work like Superman’s X-Ray Vision, or by standing 30 ft from the intended target so that the target’s body is only partially within the ring’s radius (RAW explanation). If that’s the case, do spells like Disguise Self also disguise the internal organs of an affected character in such a way as to fool a person with a Ring of X-Ray Vision?

For example, would the user of Ring of X-Ray Vision be able to tell if a target has a second heart, or has only one lung, or is undead (dead organs) if that target is affected by spells like Disguise Self?

Moreover, would a Ring of X-Ray Vision allow its user to see selectively through clothes? If so, what about illusory clothes and other illusory objects? I am thinking that it should, otherwise its wearer could use it to automatically detect any illusion, which is not what it says in the description (no truesight, just see through solid objects).

Does the Darkness spell block vision?

In discussing this question, I came to realize that the real question was whether Darkness blocks vision or merely creates “darkness”.

Per the wording of the spell:

Magical darkness spreads from a point you choose within range to fill a 15-foot-radius sphere for the duration. The darkness spreads around corners. A creature with darkvision can’t see through this darkness, and nonmagical light can’t illuminate it. (emphasis mine)

Normal darkness is defined in the game as creating a heavily obscured area and the only description added to the darkness is that it is magical, which (to me) just means that it is created by magic and is subject to the magical rules.

Darkvision is defined in the game as basically being able to see in darkness as if they were seeing in dim light. So, the text “darkvision can’t see through this darkness” merely means that it affects darkvision in the same way it affects normal vision. (See earlier versions of the spell below, which had similar wordings.)

I see nothing there that implies it is a barrier to vision, just an active and utter absence of illumination.


Previous editions have varying descriptions. What's the history of the Darkness spell? and this wiki article give accurate accountings of the various versions.

  • The 1e Wizard version seems to actually imply a sphere of opaque blackness that even blocks infra/ultravision, while the 1e Cleric version is a reversal of the Light spell and creates totally normal darkness, with no block to special visions.

  • The 2e version is similar to the 1e Cleric spell. It creates an area of darkness “equal to an unlit interior room”.

  • The 3.0e version comes closest to the 5e version. It “causes an object to radiate darkness out to a 20-foot radius. Not even creatures who can normally see in the dark (such as with darkvision) can see in an area shrouded in magical darkness.” Still no reference to any sort of opacity and the wording makes it clear that darkvision is being treated specifically here.

  • 3.5e Darkness is similar, although instead of darkness, it creates “shadowy illumination”. This affects darkvision as well as normal vision.

  • 4e doesn’t have a Darkness spell, but rather a Cleric Utility called Veil of Darkness, which creates “a zone that is heavily obscured and blocks line of sight.” So, finally, a reference to opacity, in “blocks line of sight”, although I question if opacity was the intent.

Text detection in computer vision

I’m curious about the way text recognition works in machine learning(or more generally, the question of object vs not object) in computer vision.

How are systems trained when the not-object data set is so much greater in quantity and apparently lacks structure?

One approach is having the algorithm first searches for a text box and once it finds one applies character recognition. Thus the initial classification comes down to “text” or “not text”. “Not text” doesn’t have any particular structure though and in fact almost everything is “not text”…so how is this dealt with?

What would the “not text” training set be? Random images? Clearly you need negative examples.

In Roll20, how do you restrict PC’s vision in situations like fog?

For situations like Obscuring Mist and other vision impairment that overcomes Darkvision (and similar abilities), how have you successfully enforced that in Roll20?

My PC’s would probably meta-game if they’re simply told “you can’t see in this area” and it kind of nullifies a major encounter coming up (and would be good to know for the future).

Assume Plus membership to the website (access to Advanced/Fog of War and Dynamic Lighting but not API.

Measurements of success:

  • Players are able to manipulate their token on a battle grid to explore the area of restricted sight
  • The GM can interrupt players when their sensory information changes without significantly interrupting play each round
    • Ideally, you would also avoid constantly moving them back
  • You have some method of providing information to players about what their character perceives
    • Ideally, only the player that “should” have the exact knowledge would have it, and others only what they can convey

Good answer(s) will follow the concept of Good Subjective and cover key ponts

  • What has been your experience using the system?
    • IE player feedback, how you felt it worked
  • How you were able to restrict sight and also reveal information
    • Did you just tell the one player? Did everybody get to know when Bob was next to the bad guy?

Related for physical TT

For physical games, how do you restrict PC’s vision in situations like fog?

For situations like Obscuring Mist, darkness, and other vision impairment, how have you successfully enforced that?

Measurements of success:

  • Players are able to manipulate their character on a battle grid to explore the area of restricted sight
  • The GM can interrupt players when their sensory information changes without significantly interrupting play each round
    • Ideally, you would also avoid constantly moving them back
  • You have some method of providing information to players about what their character perceives
    • Ideally, only the player that “should” have the exact knowledge would have it, and others only what they can convey

Good answer(s) will follow the concept of Good Subjective and cover key ponts

  • What has been your experience using the system?
    • IE player feedback, how you felt it worked
  • How you were able to restrict sight and also reveal information
    • Did you just tell the one player? Did everybody get to know when Bob was next to the bad guy?

Related for Roll20 Virtual TT

Difference between Image Analysis and Computer Vision

I have searched the web and I have only found the differences between Image Processing and Computer Vison (also in this website too). In addition, sometimes Image Analysis is confused with Image Processing, which is untrue. Reading the Wikipedia article, it makes me thing that Image Analysis is another name for Computer Vision. Therefore I am confused. What is the real difference of those two?