Instance Graph

The Instance Graph is instant3Dhub’s core concept to structure the data based on the linked 3D Data Resources inside a 3D Space.

The InstanceGraph is a hierarchical tree structure, which combines two major aspects, i.e. the logical representation of a scene graph and the semantic structure of 3D Data Resources like BOMs or assembly structures combined with the sub-assembly structures of the individual part structures.

For instance, to visualize geometry, an application adds the respective 3d data — linked and cached as a resource — to the Instance Graph. instant3Dhub then synchronizes and displays this content across all connected viewers. Unlike traditional scene graphs, the Instance Graph is a linked structure of data resources, designed to facilitate communication between users, applications, and synchronized clients.

Structure of the Instance Graph

The Instance Graph is a hierarchical tree made up of nodes. Each node can store metadata and transformation data and can be connected to external 3D resources (depending on its type in the structure). There are three structural node types:

  • Root Node The single root of the graph. It has no parent and cannot hold links or transformations.

  • Inner Node A node that has one or more children. It may define a transformation but does not reference a shape or a resource directly.

  • Leaf Node A node without children. It can:

    • Define a transformation

    • Hold one or more shape instances (geometry)

    • Hold a single resource link (if not the root node)

Instance Graph contents

For each node in the Instance Graph, more information related to it is defined by Shapes, AUX, Metadata and Layers. These contents represent typical information stored in the 3D Data Resources.

  • Shapes: The mathematical representation of the geometrical elements.

  • AUX: auxiliary information, typically stored as Model Views or PMIs.

  • Metadata: Supplementary information, such as names, materials, versioning or custom properties further descibing a node on root, inner or leaf level.

  • Layer: Layers allow for a selective visibility and organization of the 3D Space content on a global level. This means Layers can be used to control the display of nodes based on their properties or attributes, enabling users to focus on specific aspects enabling and disabling certain nodes and AUX.

Learn more about these contents in the respective sections of the documentation below: