Coh2 is based on a grid of 1 meter by 1 meter squares.
When an object is placed on the map, an area is painted as IMPASS. Meaning no units can go there. Another area is painted meaning that units have NO VISION. In Coh2, these two areas do not match each other. So you have areas around objects where units have NO VISION.
In the picture below the IMPASS area is painted RED. The NO VISION area is tagged with BLUE DOTS.
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You can test these bugs in the worldbuilder using the LOS tool and moving your mouse around the IMPASS grid.
You can also test these areas in game by moving a sniper around objects.
NO VISION
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WITH VISION
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When making a map for Coh2 you need to manually paint IMPASS on the areas where units can go but have no vision. This happens on many objects fuel tanks, stone walls, etc, etc, etc.
I recently saw this bug on Port of Hamburg and then tested on Ploiesti to make sure it was the Refining Tanks causing the issue.
Would be great if this bug did not persist on Coh3.