// 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);
}