Just to remember: The double height code does not allow to make double deep holes next to buildings with up down tool.
I can't manage to repeat this?
Hmm, neither can I. I am able to go down double deep (4 half height segments) beside buildings and roads fine.
(http://www.ssgholdings.ca/simutrans/images/half-height-test.png)
Use the up/down tool (u and d key binding, as I wrote), not the artifical slope tool. I will see to it anyway this evening.
I could use that near buildings too?
Ah, I see it now.
(http://www.ssgholdings.ca/simutrans/images/half-height-test-2.png)
You can only go down a half-height beside the buildings, not 2 heights (standard height).
Again, I can lower the ground to form double slopes next to buildings :s
Aha! I figured it out (after much experimentation, when retesting made it work fine for me just now)... you can lower double heights if the city object (building/road) is at an odd level (-1,1,3,etc) but only half height if it's at an even numbered level (-2,0,2,etc).
Even then I seem to be able to? :s
It just happens next to a road/building and when start is one level above sea level. Higher levels are not affected. Although even stepping through a little seems not too wrong. It seems however, want to lower a corner, although is does not at the end.
Ah ha could finally confirm this!
Ok - setting water height to this tile to be grundwasser-4 when land fixes this. This is easy enough to do for new maps but existing ones will either need converting or just have to deal with bug.
Edit2: Committed fix to new maps in 6866.