This is a question - not an answer.

As far as I can detect in the software (DD2) there are no gaps in the walls.

I need to add contrast to the map, to make the passages more visible (I would prefer staying within CC2, if possible). To do this, I have been informed that I need to create a multipoly of the current dungeon level, to place in front of a tinted background.

Problem: In attempting to create the multipoly, it bleeds in 4/5 places (I think). Any idea how to fix the walls so that they are amenable to the multipoly?

I have attached a current map to illustrate - all thoughts are welcome.Click image for larger version. 

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