# Data Model

Table of Contents

- Overview
- Model Tree
  - Overview
  - Nodes
  - NodeIDs
  - Node hierarchy
  - Instancing
  - Callbacks
  - Node creation
- Instancing
  - Creating multiple instances from a part of a model
  - Full instancing source code
- Layers and filters
  - Filters
  - Retrieving filters
  - Filtering nodes
  - Layers
  - Retrieving layers
  - Retrieving nodes per layer
- Model Units
  - Overview
  - Working with model units
  - Multiple units with model aggregation
- Metadata
  - Overview
  - Retrieving properties
  - Retrieving user data
- Drawings
  - Identifying a drawing
  - Drawing UI
  - Sheets
- Stream Cache
  - Overview
  - Loading
  - Loading subtrees
  - Shattered Workflows
  - SC and PRC

This is the Programming Guide for the Data Model of the Web Viewer API.

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