yeah, sorry for missing this
I will re-release GH3 completely redrawn in 1024x1024 with GH2 cities, but that's the future
Now the thing that is important are indeed bitmap (.bmp) or targa (.tga) graphics files calls in all tiles listed in the terrains' _data.ini files -city textures are those with "C" in name, example VietnamC1.bmp or VietnamSC25a.tga -so for these files ou need to copy/paste the graphic filenames calls from GH2
I'm at work currently but will send my version of the GH3 with GH2 buildings I have in my install later, here's example:
[Texture036]
Filename=vietnamSC25A.TGA
HasWater=1
HeightMap=vietnamSC25A_hm.BMP
HeightMapScale=25.000000
Color=0.287661,0.338985,0.352909
SolidObjectTexture=terobject_buildings1.BMP
AlphaObjectTexture=terobject_trees1.TGA
the lines in red in GH3 _data.ini must match those found in GH2 _data.ini for all Vietnam-whatever-C tiles