Hello, is the following a valid LOS? one of the lines crosses a black wall corner (the left one)

Just now, topacesteve said:

Hello, is the following a valid LOS? one of the lines crosses a black wall corner (the left one)

Sorry, i didnt notice the RED BLOCK..lets assume the RED obstacle was not there....

Asking to find whether a space has line of sight to another space would be clearer.

No, there is no line of sight (even if you remove the blocking space) due to not being able to draw line of sight through walls ('glancing' them is ok). I.e. the bottom line is ok, but the upper line is not.

basically i was referring to this from the RRG. is this still valid????

The examples in RRG are valid. There is no blocking terrain between the line of sight lines, and the examples do not draw line of sight through walls, doors, blocking terrain or energy shields.

I assume you're referring to the left of the two images in the example.

Look at it this way: where the two white lines which indicated the spaces would meet at a corner like that is a valid corner for line of sight. The black wall extending outward is purely graphical, which is why (as a1bert stated) the bottom line of your original image is a valid line, but the top line is not.