This is an error that is technically in the art files. The tranistion tiles for that mountain to sand corner is too small. There is only a couple of pixels of mountain in it. This makes it look like there is a pure sand tile there. You can fix these with another tile piece, but I'm not sure if it's 3D compliant or not.
Dragon scripts by default use the adjacent tile set for the transitions. You will need to make the following changes to the mountain to desert transition script. sand2mountain.txt in the older ones and mountain2sand.txt in mod 11.
012A -> 07BE
012B -> 07B0
012C -> 07BD
012D -> 07BF
I have never checked to see what these tiles look like in the 3D client, but I'd be willing to bet they are not supported and you'll see lava tiles (3D client's replacement tile for unknown) instead. If you are only going to use the 2D client then this should fix your problem.
Here's a snippet to show what I'm talking about.
Quote:
// NE corner is TileA
BAAABBBB 012d -02 002
AAAABBBB 012d -02 002
BAAAABBB 012d -02 002
AAAAABBB 012d -02 002
AAAAABAB 012d -02 002
BAAABAAB 012d -02 002
BAAABBBA 012d -02 002
BAAAABBA 012d -02 002
BAAAABAA 012d -02 002
AAAABABB 012d -02 002
BAAABABB 012d -02 002
BAAABBAA 012d -02 002
BAAABBAB 012d -02 002
AAAABBAB 012d -02 002
AAAABAAB 012d -02 002
BAAABABA 012d -02 002
BAAAABAB 012d -02 002
It should be changed to read:
Quote:
// NE corner is TileA
BAAABBBB 07BF -02 002
AAAABBBB 07BF -02 002
BAAAABBB 07BF -02 002
AAAAABBB 07BF -02 002
AAAAABAB 07BF -02 002
BAAABAAB 07BF -02 002
BAAABBBA 07BF -02 002
BAAAABBA 07BF -02 002
BAAAABAA 07BF -02 002
AAAABABB 07BF -02 002
BAAABABB 07BF -02 002
BAAABBAA 07BF -02 002
BAAABBAB 07BF -02 002
AAAABBAB 07BF -02 002
AAAABAAB 07BF -02 002
BAAABABA 07BF -02 002
BAAAABAB 07BF -02 002