I tried to make a field, slightly bumpy, with sandbox. Knowing my sketchuppies, I made sure the white side was facing up and the blueish side was facing down. When Setting the skatter to use something in between “up” and “normals”, all grass was laying on its side. After a while I found out this was solved when I reversed the surface…
Could you send me the file?
You might also want to check the axies of the scattered object.
The scattered object is from the library that comes with Skatter. The proxy object looks topsy turvy as well. Where can I send the file to?
We have the file, thanks!
Thomas will take a look 
Did you create the terrain with Sandbox?
Well I created it with sandbox at first but then subdivided it with artisan after, since I wasn’t content with the level of detail.
That shouldn’t make a difference though, should it?
It shouldn’t, but I think I saw unexpected stuff like this in the past.
In the meantime, you can explode the terrain group/comp and, regroup it, and repick it in Skatter.