public sealed class LasPointFilter 

// search all points
using (ArcGIS.Core.Data.Analyst3D.LasPointCursor ptCursor = lasDataset.SearchPoints(null))
{
  while (ptCursor.MoveNext())
  {
    using (ArcGIS.Core.Data.Analyst3D.LasPoint point = ptCursor.Current)
    {

    }
  }
}

// search within an extent
ArcGIS.Core.Data.Analyst3D.LasPointFilter pointFilter = new ArcGIS.Core.Data.Analyst3D.LasPointFilter();
pointFilter.FilterGeometry = envelope;
using (ArcGIS.Core.Data.Analyst3D.LasPointCursor ptCursor = lasDataset.SearchPoints(pointFilter))
{
  while (ptCursor.MoveNext())
  {
    using (ArcGIS.Core.Data.Analyst3D.LasPoint point = ptCursor.Current)
    {

    }
  }
}

// search within an extent and limited to specific classification codes
pointFilter = new ArcGIS.Core.Data.Analyst3D.LasPointFilter();
pointFilter.FilterGeometry = envelope;
pointFilter.ClassCodes = new List<int> { 4, 5 };
using (ArcGIS.Core.Data.Analyst3D.LasPointCursor ptCursor = lasDataset.SearchPoints(pointFilter))
{
  while (ptCursor.MoveNext())
  {
    using (ArcGIS.Core.Data.Analyst3D.LasPoint point = ptCursor.Current)
    {

    }
  }
}

// search all points
using (ArcGIS.Core.Data.Analyst3D.LasPointCursor ptCursor = lasDataset.SearchPoints(null))
{
  int count;
  Coordinate3D[] lasPointsRetrieved = new Coordinate3D[10000];
  while (ptCursor.MoveNextArray(lasPointsRetrieved, null, null, null, out count))
  {
    var points = lasPointsRetrieved.ToList();
  
    // ...
  }
}

// search within an extent
// use MoveNextArray retrieving coordinates, fileIndex and pointIds
ArcGIS.Core.Data.Analyst3D.LasPointFilter filter = new ArcGIS.Core.Data.Analyst3D.LasPointFilter();
filter.FilterGeometry = envelope;
using (ArcGIS.Core.Data.Analyst3D.LasPointCursor ptCursor = lasDataset.SearchPoints(filter))
{
  int count;
  Coordinate3D[] lasPointsRetrieved = new Coordinate3D[50000];
  int[] fileIndexes = new int[50000];
  double[] pointIds = new double[50000];
  while (ptCursor.MoveNextArray(lasPointsRetrieved, null, fileIndexes, pointIds, out count))
  {
    var points = lasPointsRetrieved.ToList();

  }
}
      

// searching on the LasDatasetLayer will honor any LasPointDisplayFilter

// search all points
using (ArcGIS.Core.Data.Analyst3D.LasPointCursor ptCursor = lasDatasetLayer.SearchPoints(null))
{
  while (ptCursor.MoveNext())
  {
    using (ArcGIS.Core.Data.Analyst3D.LasPoint point = ptCursor.Current)
    {

    }
  }
}

// search within an extent
ArcGIS.Core.Data.Analyst3D.LasPointFilter pointFilter = new ArcGIS.Core.Data.Analyst3D.LasPointFilter();
pointFilter.FilterGeometry = envelope;
using (ArcGIS.Core.Data.Analyst3D.LasPointCursor ptCursor = lasDatasetLayer.SearchPoints(pointFilter))
{
  while (ptCursor.MoveNext())
  {
    using (ArcGIS.Core.Data.Analyst3D.LasPoint point = ptCursor.Current)
    {

    }
  }
}

// search within an extent and limited to specific classification codes
pointFilter = new ArcGIS.Core.Data.Analyst3D.LasPointFilter();
pointFilter.FilterGeometry = envelope;
pointFilter.ClassCodes = new List<int> { 4, 5 };
using (ArcGIS.Core.Data.Analyst3D.LasPointCursor ptCursor = lasDatasetLayer.SearchPoints(pointFilter))
{
  while (ptCursor.MoveNext())
  {
    using (ArcGIS.Core.Data.Analyst3D.LasPoint point = ptCursor.Current)
    {

    }
  }
}

// search all points and process with a set size of array retrieving only coordinates
using (ArcGIS.Core.Data.Analyst3D.LasPointCursor ptCursor = lasDatasetLayer.SearchPoints(null))
{
  int count;
  Coordinate3D[] lasPointsRetrieved = new Coordinate3D[10000];
  while (ptCursor.MoveNextArray(lasPointsRetrieved, null, null, null, out count))
  {
    var points = lasPointsRetrieved.ToList();

    // ...
  }
}

// search within an extent
// use MoveNextArray retrieving coordinates, fileIndex and pointIds
ArcGIS.Core.Data.Analyst3D.LasPointFilter filter = new ArcGIS.Core.Data.Analyst3D.LasPointFilter();
filter.FilterGeometry = envelope;
using (ArcGIS.Core.Data.Analyst3D.LasPointCursor ptCursor = lasDatasetLayer.SearchPoints(filter))
{
  int count;
  Coordinate3D[] lasPointsRetrieved = new Coordinate3D[50000];
  int[] fileIndexes = new int[50000];
  double[] pointIds = new double[50000];
  while (ptCursor.MoveNextArray(lasPointsRetrieved, null, fileIndexes, pointIds, out count))
  {
    var points = lasPointsRetrieved.ToList();

  }
}