It's a glitch in Blitz. If you monkey with terraindetail you might find a value to ramp it down instead of up. Otherwise you're going to have to hide it, or use a mesh. I recommend the mesh.
heightmap bother
Blitz3D Forums/Blitz3D Programming/heightmap botherThe forum is locked. These are the original blitzbasic.com forums, kept so they can still be read. No new topics, replies or edits can be made here. To join in, head over to the Blitz3D+ forums.