Organizes
In OPC UA, Organizes is the hierarchical ReferenceType expressing loose membership: the target node appears under the source, typically a Folder, without being a part of it. It is identifier i=35 in namespace 0, with the inverse name OrganizedBy. It is how the ObjectsFolder and every other folder gets its contents.
Filing, not composition
Organizes says only that a node is listed here. The same node may be organised into several folders at once, and removing it from a folder does not delete it. That is the whole difference from HasComponent, which says the target is a constituent part whose lifetime is bound to its parent. Folders - Objects of FolderType - use Organizes for their children by convention and by definition.
The standard skeleton is built from it
The RootFolder at i=84 organises the ObjectsFolder at i=85, the TypesFolder at i=86 and the ViewsFolder at i=87. Every browse of an unfamiliar server therefore begins by following Organizes references from i=84. open62541's own hello-world creates its first Variable with UA_NS0ID(OBJECTSFOLDER) and UA_NS0ID(ORGANIZES) for exactly this reason.
It makes the address space a graph
Because Organizes is many-to-many, a node can be reached by more than one path, and a recursive browser without a visited-set will emit duplicates or loop. Servers may set the ContainsNoLoops attribute on a View to promise otherwise, but nothing promises it for the general address space. Keep a set of visited NodeIds in any traversal you write.
Example
The standard folder skeleton, all built from Organizes
Root i=84 FolderType
+--Organizes--> Objects i=85
| +--Organizes--> Server i=2253
| +--Organizes--> Machines (vendor folder)
| +--Organizes--> Mixer_01
+--Organizes--> Types i=86
| +--Organizes--> ObjectTypes, VariableTypes,
| ReferenceTypes, DataTypes, EventTypes
+--Organizes--> Views i=87
Mixer_01 may also be Organizes-referenced from a Line3 folder.
One node, two paths, same NodeId - this is a graph.Defined in: Part 3 - Address Space Model, standard ReferenceTypes; Part 5 - Information Model for the standard folder hierarchy.
Last verified 7 September 2026 against OPC UA 1.05.07. OPC UA Connect is an educational resource and is not affiliated with the OPC Foundation.