public LASStretchType StretchType {get; set;}

// applies to LAS dataset layers only

var elevLasStretchRendererDef = new LasStretchRendererDefinition(ArcGIS.Core.CIM.LASStretchAttribute.Elevation);
// accept the defaults for color ramp, etc

if (lasDatasetLayer.CanCreateRenderer(elevLasStretchRendererDef))
{
  CIMTinRenderer renderer = lasDatasetLayer.CreateRenderer(elevLasStretchRendererDef);
  if (lasDatasetLayer.CanSetRenderer(renderer, SurfaceRendererTarget.Points))
    lasDatasetLayer.SetRenderer(renderer, SurfaceRendererTarget.Points);
}


// OR use a stretch renderer with stretchType standard Deviations
var elevLasStretchStdDevRendererDef = new LasStretchRendererDefinition(ArcGIS.Core.CIM.LASStretchAttribute.Elevation);
elevLasStretchStdDevRendererDef.StretchType = LASStretchType.StandardDeviations;
elevLasStretchStdDevRendererDef.NumberOfStandardDeviations = 2;
// accept the defaults for color ramp,  etc

if (lasDatasetLayer.CanCreateRenderer(elevLasStretchStdDevRendererDef))
{
  CIMTinRenderer renderer = lasDatasetLayer.CreateRenderer(elevLasStretchStdDevRendererDef);
  if (lasDatasetLayer.CanSetRenderer(renderer, SurfaceRendererTarget.Points))
    lasDatasetLayer.SetRenderer(renderer, SurfaceRendererTarget.Points);
}