Wink Brace's page

I have always broken traps down into two categories. 'Visible' and 'invisible'

Visible traps can be seen if you are looking at it. tripwires, gaps in walls where sawblades jump out, swords hanging overhead by thin wires etc. The clues that a trap is there is obvious...if you are looking. as a result, I allow a rwactive perception check. the difficulty is not always good (after all traps only work if they are not usually spotted) but once seen the PC's can react as they choose.

Invisble traps cannot be seen without some pretty detailed investigation. Hidden trap doors under the rug, or poison gas that shoots out of a lock. these traps can be found only when the PC actively declares he is looking for them (af course the aforemetioned rogue talent is an obvious exception).

Batts

I know this topic is five years old, but this answer is exactly what I was looking for. This is precisely how I am going to play traps from now on. I like it a lot. :)