I have a terrain model in which it includes a hole.
The hole is introduced by adding a FeatureMaskLayer layer.
The problem arises when representing it. It seems to work perfectly, but at certain zoom levels it represents the hole badly.
In this figure the display is ok.
On this other zoom the hole is bad represented.
When i zoom in the error disappears.
Could you please tell me some solution ?
Just a guess, but to me this looks like an error caused by precision loss. The MaskGenerator that osgEarth uses to cut holes uses OSG's osgUtil::DelaunayTriangulator internally; that class operates on single-precision floating point coordinates. So it's quite possible that the operation is introducing errors by truncating the input values.
Assuming this is the issue, I'm sorry but we don't have an easy fix at the moment! I recommend logging a GitHub issue (include your sample earth file -- no need for the imagery) so we can track it.