public override List<Type> AllowedConstraintTypes()
{
RebarShapeDefinitionByArc definitionByArc = RebarshapeDefinition as RebarShapeDefinitionByArc;
List<Type> allowedTypes = base.AllowedConstraintTypes();
allowedTypes.Add(typeof(ConstraintRadius));
allowedTypes.Add(typeof(ConstraintDiameter));
allowedTypes.Add(typeof(ConstraintArcLength));
allowedTypes.Add(typeof(ConstraintCircumference));
allowedTypes.Add(typeof(ConstraintChordLength));
allowedTypes.Add(typeof(ConstraintSagittaLength));
return allowedTypes;
}