private static BoundingBox RoundToAdtBounds(BoundingBox bounds)
{
bounds.Minimum.X = (float)(Math.Round(bounds.Minimum.X/AdtWidth)*AdtWidth);
bounds.Minimum.Y = (float)(Math.Round(bounds.Minimum.Y/AdtWidth)*AdtWidth);
bounds.Maximum.X = (float)(Math.Round(bounds.Maximum.X/AdtWidth)*AdtWidth);
bounds.Maximum.Y = (float)(Math.Round(bounds.Maximum.Y/AdtWidth)*AdtWidth);
return bounds;
}