Is Detect barrier-penetrating by default?

[Toptomcat]

Will vanilla Detect work through walls, earth, six feet of lead, etc.? If so, what would be the appropriate value be for a limitation that didn't? If not, what would be the appropriate value be for an enhancement that did?

[weby]

Well, the wording strongly implies that it does not care for barriers.

As for values, it depends really on how limiting the condition is. In general it would thus be Accessibility limitation. As a reference on one possible value: if you need to see the thing with your eyes it would be Sense-Based, Reversed (single sense)(PU8 p17) -20%.

[David Johnston2]

It is, yes. After all, it's how you do dowsing.

[Not another shrubbery]

Originally Posted by weby

Well, the wording strongly implies that it does not care for barriers.

As for values, it depends really on how limiting the condition is. In general it would thus be Accessibility limitation. As a reference on one possible value: if you need to see the thing with your eyes it would be Sense-Based, Reversed (single sense)(PU8 p17) -20%.

Yeah. The first line in Basic is supposed to convey that but it's not necessarily obvious. Reverse Sense-Based is a useful model for limited forms of Detect like the op was asking about. You can also look at Restricted Arc (from Enhanced Senses, a useful reference for this subject) and Short-Range from Powers. Having an insulator that blocks the Detect will usually be a Nuisance Effect unless it is very common.

[Pursuivant]

Originally Posted by Toptomcat

Will vanilla Detect work through walls, earth, six feet of lead, etc.? If so, what would be the appropriate value be for a limitation that didn't? If not, what would be the appropriate value be for an enhancement that did?

Per RAW, "You can detect a specific substance or condition, even when it is shielded from the five human senses."

That implies that Detect ignores barriers, which is appropriate for magical and psi powers which ignore the laws of physics.

For realistic or super powers, the Special Limitations for Penetrating Vision might be applicable: -10 to -30% for Blockable, -10% to -80% for Specific.

A new special limitation to Detect, "Limited by barriers" might be worth -5% per -1 penalty for intervening barriers. That's in line with the -5% per level for generic limitations like Inaccurate or Resistible. How the -1/lvl penalty is assessed depends on how the specific Detect power works, it could be -1 per inch or foot of material or -1 per barrier no matter how thick it is.

For Detect powers which are specifically based on normal senses, it seems logical to apply the Sense-Based limitation (i.e., -30% for one sense, -20% for two, or -10% for 3) in some cases.

For example, if you can Detect magic using your eyes (a ranged, more accurate version of Mage-Sight) buy Detect with a -30% limitation. This allows you to can see major sources of magical emanations in the open (e.g., Octarine light flooding the Discworld, magical auras from huge area enchantments, regions of Very High Mana) at great distances in good sighting conditions, but can't see them if they're covered up, far away, or if you're blindfolded, or operating in bad weather or the dark.

[Not another shrubbery]

Originally Posted by Pursuivant

For realistic or super powers, the Special Limitations for Penetrating Vision might be applicable: -10 to -30% for Blockable, -10% to -80% for Specific.

Good call on using the Penetrating Vision limiters, although I'm having trouble wrapping my head around applying Specific to it. A Block seems like it might be more limiting to a Detect, since it doesn't register anything if something is shielded from the sense.

[Polkageist]

Having specific (rare?) materials capable of blocking Detect spells and abilities is a good plot hook as well.