Avoid Distance Field glitches in over scaled meshes

Hi everyone,

http://i.imgur.com/qgKEzQwm.jpg

as you can see I used a basic rock mesh from the kite demo to create large mountains. This results however in very dark zones as the image shows above.

I also tried to create a duplicate of the rock mesh and change build scale to 45 and use it in the world. Didn’t changed anything.

Any idea?

Thanks