// public ElasticNode(MKENodeType t = MKENodeType.uv) { id = 0; Type = t; x1 = x2 = u = v = fiu = fiv = fx = fy = mxz = myz = double.NaN; }
// public ThermoNode(MKENodeType type = MKENodeType.t) { id = 0; Type = type; x1 = x2 = t = double.NaN; }