Darkvision question

[Splendor]

Last weekend in a game we had a player believe that 60' darkvision started from the end of a light source and extended 60'.

So if he had a torch with a (20' radius light source) he could see out to 20' like everyone else and then could see 60' with darkvision, for a total of 80'.

Is there anywhere something like this is written?

[Zexion]

It does not extend from the end of a light source. It overlaps.

[Dr Bwaa]

It is a 60-foot cone, representing a field of vision. It would make no sense for a cone of vision to begin at the edge of a circle. Also, it would make no sense in general. Darkvision overlaps with normal and low-light vision.

Darkvision is the extraordinary ability to see with no light source at all, out to a range specified for the creature. Darkvision is black and white only (colors cannot be discerned). It does not allow characters to see anything that they could not see otherwise—invisible objects are still invisible, and illusions are still visible as what they seem to be. Likewise, darkvision subjects a creature to gaze attacks normally. The presence of light does not spoil darkvision.

I think this is as clear as you're likely to get, but it's pretty clear--80 feet is not within "out to a range of 60 feet."