public class TinEdgeRendererDefintion : TinSimpleRendererDefinition 

//Must be on the QueuedTask.Run()

var lasCP_renderers = new LasDatasetLayerCreationParams(lasDataset);
lasCP_renderers.Name = "My LAS Layer";
lasCP_renderers.IsVisible = false;

// create a point elevation renderer
var ptR = new LasStretchRendererDefinition();
// accept all defaults

// create a simple edge renderer
var edgeR = new TinEdgeRendererDefintion();
// accept all defaults

// add renderers to dictionary
var l_dict = new Dictionary<SurfaceRendererTarget, TinRendererDefinition>();
l_dict.Add(SurfaceRendererTarget.Points, ptR);
l_dict.Add(SurfaceRendererTarget.Edges, edgeR);

// assign dictionary to creation params
lasCP_renderers.RendererDefinitions = l_dict;

//Create the layer to the LAS dataset
var lasDatasetLayer_rd = LayerFactory.Instance.CreateLayer<LasDatasetLayer>(lasCP_renderers, map);

// applies to TIN or LAS dataset layers only

var edgeRendererDef = new TinEdgeRendererDefintion();
edgeRendererDef.Description = "Edges";
edgeRendererDef.Label = "Edges";
edgeRendererDef.SymbolTemplate = lineSymbol.MakeSymbolReference();

if (surfaceLayer.CanCreateRenderer(edgeRendererDef))
{
  CIMTinRenderer renderer = surfaceLayer.CreateRenderer(edgeRendererDef);
  if (surfaceLayer.CanSetRenderer(renderer, SurfaceRendererTarget.Edges))
    surfaceLayer.SetRenderer(renderer, SurfaceRendererTarget.Edges);
}