Wall ability pathing problem

[WhiteDeath]

I want to make an ability that summons a wall(a bunch of units positioned in a line perpendicular to the line between the caster and the target point of the ability). The problem is that when I summon the units if there are trees in the position where they should be summoned they are summoned around the trees, what I want is if there are obstacles in the summoning point than the unit should not be created.
I tried with checking the pathing of the summoning points and it works for terrain(cliffs) that is unwalkable but it does not detect the trees as unwalkable.

 

[WaterKnight]

Well check if the coordinates differ after creating them (to immediately destroy them again). That is the most sure way to know whether the path is exactly blocked for this object but a common method is to place a dummy item for ground pathing.

 

[WhiteDeath]

Thank you.