"Great Size Lines of fire drawn to or from this character are not blocked by elevated terrain or outdoor blocking terrain, and are hindered only if the line of fire is drawn to a square of hindering terrain that includes the target." On maps that are both indoor/outdoor or outdoor/indoor if one figure is indoor the other outdoor is line of fire only concerned with the blocking terrain being outdoor? On the "Mighty Thor" map "GJALLERBRU" the bridge has walls (blocking) on each side. Can great size line of fire be drawn from one side to the other (both figures outdoor) because the walls are treated as both indoor blocking and outdoor blocking?

Your giant is indoors behind the blocking. You would not be seen.

It's one of the weird mechanics that doesn't translate as well on an indoor/outdoor map as you can "see" over any buildings... except those you can go inside. But yes, if there is any indoor blocking (like on the bridge) between a figure with great size and anything else on the other side of that indoor building, LOF is blocked.

Thanks for the response. But, ok the giant as you say is indoors wear is the blocking? And does that only block if the great size figure is indoor?

Rulebook pg. 25-

I'm sorry guys, my first question was intended to be separate. One figure indoor the other one is outdoor with line of fire not going through a wall. I place barrier in outdoor squares, is line of fire blocked?

When it comes to great size, any blocking having to do with indoor (including the wall separating indoor from outdoor) will block LoF.
If you're shooting through a doorway where there is no indoor wall and the only blocking between them is outdoors, the LoF is not blocked.