message: hm - nullptr isn't good either...
diff: @@ -172,7 +172,7 @@ namespace ospray {
  if (node.name == "Integrator")
  return parseIntegratorNode(node);
  std::cout << "warning: unknown sg::Node type '" << node.name << "'" << std::endl;
  - return nullptr;
  + return std::shared_ptr<sg::Node>();
  }
  std::shared_ptr<sg::World> loadOSP(const std::string &fileName)
  