You could think of it as separate early 'bastions' (perhaps something star-shape fortress alike) becoming connected over time with full-scale trenches like you're creating now.
Well, star-shaped forts were really outdated at the time of world war one
They were already outdated in the 19th century, due to the increased power of artillery shells, which have an easy target in the large walls of such a fort. Forts of ww1 were all built deeply into the ground with the greatest part hidden and protected under large amounts of earth and concrete. Only some defensive pillboxes for artillery and machine guns and observers were visible from the outside. However, even after the invention of steel reinforced concrete, a fortress could only withstand the huge calibres for so long (see
Fort Douaumont)
I think the RoM(or was it the WWII 1939 team) team have created something like trenches(Infantry can build forts/trenches/bunkers/bunker systems, like a worker builds a fort).
Thanks for the hint
I took a look at how they did it in WWII 1939 (couldn't find any trench stuff in RoM) and it seems they just use a single "fort-like" improvement:
Looks pretty nice, but "real" trench systems are still better
About my previous idea for making holes:
It is not that simple. It
might work with a combination of stencil buffer + z-buffer and exploiting the fact that the trenches are the ultimate background (nothing will be drawn behind them) and using intermediate geometry writing to the stencil buffer to prevent the trench faces from overwriting closer faces. It would require some shader coding, even though that shader would be very simple (doesn't even need a fragment shader), which might be annoying for people with older hardware. So, i guess this could be an option for a later time, but right now it's not really worth the effort.
Now for some good news: besides the trenches, i also started work on a "Nomansland" terrain type. I made a python script for blender to create a shell cratered landscape, which could replace the original fertile soil after prolonged bombardment. Enjoy
I want to improve my barbed wire on the trenches, more like these:
http://en.wikipedia.org/wiki/File:German_stormtroops_training_Sedan_May_1917_3.jpg
After some finishing touches on the textures and making a second variation, i guess i can then upload the first version. Btw. do you know if it's possible to replace files in the civfanatics database with newer versions for that purpose?
