This was mentioned before but there is a great video on the line/block construction system in Spring. http://youtu.be/3IVaKPjpsHU?t=1m30s Summary: Hold shift to make a line, hold shift+alt to make a block and press z or x to increase or decrease the space between buildings, respectively. This could also be combined with a hold Ctrl command to change facing direction.
Re: Building Lines and Blocks UI wouldn't that is something that will make pa into simcity with robots? think of all the corridors you will create, the small streets, the bottlenecks inside your base, the ai going crazy, traffic jam... AHHH its a NIGHTMARE i think this shouldn't get in the game.
Re: Building Lines and Blocks UI Maybe I didn't explain this properly. This is a UI feature, similar to the repeat queue on factories or the existing hold shift and drag in Supreme Commander. Gameplay should be a function of balance and game mechanics like asteroids - not obstruction by the UI. This is not StarCraft.