Overview

The Model Tree (Tree Widget) in the iModel Viewer is a visual tool that helps you explore, understand, and interact with the structure of your digital twin. It organizes model data into a hierarchical format, making it easy to find, view, and manage elements.

Getting Started

Requirements

• Access to an iModel Viewer (e.g., iTwin Viewer, Infrastructure Cloud, CONNECT)
• Loaded an iModel

Opening the Model Tree

1. Launch your iModel Viewer.
2. Locate the Tree Widget panel (usually on the right).
3. If hidden:
   • Click the Widgets or Tools icon.

Understanding the Tree Structure

The tree is organized into:

• Models: Civil, Architectural, Structural, MEP, etc.
• Categories: Roads, Rail, Drainage, Walls, Doors, Pipes, etc.
• Elements: Individual objects like Railing02, Wall01 or Beam03

Each section can be expanded to reveal nested items.

Key Features

Feature	Description	How to Use
Expand/Collapse	View nested elements	Click the arrow (▸) beside a group
Select Elements	Highlights in 3D view	Click on the item
Right-Click Menu	Actions like isolate, hide, zoom	Right-click on an element
Search Bar	Find elements by name or ID	Use the search box at the top
Visibility Toggle	Show/hide elements	Click the eye icon 👁

Common Actions

1. Zoom to Element
   • Right-click → Zoom to
   • Centers and zooms in on the selected item
2. Hide Element
   • Right-click → Hide
   • Temporarily removes the item from view
3. Isolate Element
   • Right-click → Isolate
   • Hides all other elements except the selected one
4. Reset View
   • Right-click → Reset View
   • Restores visibility to all elements

Viewer Controls Explained

These controls are typically found in the Tree Widget toolbar or context menu. They help you manage what’s visible in the 3D or 2D view.

1.     Show All

• What it does: Makes all elements in the model visible again.
• When to use it: After hiding or isolating elements and you want to reset the view.
• How to use: Click the Show All button in the toolbar or right-click in the tree and select Show All.

2.     Hide All

• What it does: Hides all elements in the model from the view.
• When to use it: To start with a clean slate or focus on adding elements back one by one.
• How to use: Click Hide All in the toolbar or right-click and choose Hide All.

3.     Invert

• What it does: Reverses the visibility of all elements—visible elements become hidden, and hidden ones become visible.
• When to use it: To quickly flip your current view and focus on what was previously hidden.
• How to use: Click the Invert button in the toolbar.

4.     Toggle 2D Views

• What it does: Shows or hides 2D views (like floor plans or section drawings) in the viewer.
• When to use it: When you want to switch between 3D and 2D representations or reduce clutter.
• How to use: Click the Toggle 2D Views button. This affects only 2D models.

5.     Toggle 3D Views

• What it does: Shows or hides 3D models in the viewer.
• When to use it: To focus on 2D drawings or isolate specific 3D content.
• How to use: Click the Toggle 3D Views button.

6.     Enable Instance Focus Mode

• What it does: Filters the Models tree to display only the elements currently selected in the model viewport.
• When to use it: Use this mode when you want to isolate and work with specific elements without distraction from the rest of the model structure in the Model Tree widget.
• How to use: Toggle Focus Mode on or off using the button in the component’s header. Note that enabling Focus Mode will automatically disable the Search feature, as the two cannot be used simultaneously. 

Quick Summary of Controls

Control	Purpose	Typical Use
Show All	Restore visibility	After hiding or isolating elements
Hide All	Hide everything	Start fresh or reduce clutter
Invert	Flip visibility	Focus on hidden elements
Toggle 2D Views	Show/hide 2D drawings	Switch between 2D and 3D
Toggle 3D Views	Show/hide 3D models	Focus on 2D or reduce load
Instance Focus Mode	Highlight one element	Inspect or present a single item

Smart Tips

• Use partial names in search (e.g., “beam” finds Beam01, Beam02)
• Grouping may vary by project (discipline, location, system)
• Toggle entire categories to manage visibility (e.g., hide all doors)

Frequently Asked Questions (FAQs)

Q1: Why is my model empty or missing elements?

A: You may have hidden elements. Right-click in the tree and select Reset View.

Q2: How do I find a specific item quickly?

A: Use the Search Bar at the top of the tree. You can search by name or ID.

Q3: Can I hide multiple elements at once?

A: Yes. Select a category or model group and use the eye icon or right-click → Hide.

Q4: What does “Isolate” do?

A: It hides everything except the selected item, helping you focus on it.

Q5: Can I customize the tree structure?

A: Not directly in the viewer. The structure is defined by Data structure from the source CAD models through the iModel Synchronization process.

Q6: Can I export or save my tree view?

A: Not currently supported.

Important Note: Hierarchy Level Size Limiting

To ensure performance and responsiveness, the Tree Widget limits the number of child nodes that can be loaded at any one level in the hierarchy. By default, this limit is set to 1000 items per level.

What This Means for You:

• If a category or model contains more than 1000 elements, not all items will be shown in the tree.
• This does not affect the 3D model—all elements are still present and viewable in the viewer.
• You may see a message like “Too many elements to display” or notice that some items are missing from the tree.

What You Can Do:

• Use the Search Bar to find specific elements by name or ID.
• Ask your Bentley Account Manager or raise a ServiceNow support ticket to raise the limit, but this may affect the overall performance of the iModel Viewer on large iModels.