Maps being made by hand without sophisticated tools risk being imperfect. Most people wouldn't notice and wouldn't be bothered by it. I am, because in some circumstances the issues are very big, even for very frequently played maps. And, if it was possible to make near-perfect symmetry-maps, why wouldn't you want to?
This is a gallery of my symmetry-analysis of some well-known CnC maps. It did surprise me how some well-known maps aren't completely symmetric (e.g. Haos Ridges) Download the files, open in Paint, and zoom in so you can see the pixels:
http://imgur.com/a/oeDGK
The first time I did this was for my re-touch of Psydev's Manufacturing Consent, which you can find here:
http://resource.openra.net/maps/5942/
Top: Manufacturing Consent. Cliffs are cyan, tiberium is red
Middle: Same as before, plus super-imposed flipped-versions (light grey), and my hand-drawn average (black)
Final: Manufacturing Consent 2.0 (black hand-drawn average from Middle).
As always, I prefer balance and fairness over prettiness. I feel the selection of tiles is quite limited (the original assets ARE pretty dated), meaning there can be lots of pressure to break symmetry because you're missing the right shape of tile.
I've attached my instructions on analysing map symmetries, and how to copy over the coordinates of the different pixels into OpenRA: [see attached How_To_Map.txt file]
I could easily hard-code a bash script dependent on the specific colors people pick. I'm using Paint.net defaults, so I'll get around to that at some point.
