I'm going to ask a very dumb question but I'm a visual guy, not a programmer, so cut me some slack .... It made me wonder when I read this if it is possible/beneficial to create a 'potential nodes' map by painting say red paths on an bmp around obstacles and so on -like the placement map for trees idea, placed on terrain as a layer- then a player scans this map for the nearest red pixel (which is the path painted on this map) and then builds nodes along this 'path' when needed? This way you wouldn't have to have a huge amount of nodes ahead of time, just build a branch using the 'node placement map' when needed? Don't shoot if it is a wacky idea!