See the Pen Forge Viewer v7: Enumerate Fragments by Petr Broz ( on CodePen.įragments in both 3D and 2D models are encapsulated in class. Here's an example of recursively traversing the entire hierarchy starting from the root object, and logging the ID and child count of each object along the way: viewer.addEventListener(_TREE_CREATED_EVENT, function () ,Ĭonsole.log('dbId:', dbId, 'fragIds:', fragIds) Note: the instance tree is loaded asynchronously, independently from actual geometry data, so wait until it's available by waiting for the OBJECT_TREE_CREATED_EVENT event. Instances of this class - retrieved from individual models in the viewer using model.getInstanceTree() - can be queried for information like parent-children relationships between objects, or object-fragment mappings. Model hierarchy of 3D models is encapsulated in class.

Generally, the relationship between objects and fragments is many-to-many: one object may consist of multiple fragments (usually for 3D objects with large number of triangles or multiple materials), and many objects may be consolidated in a single fragment (usually in 2D models). When working with Viewer APIs, you typically reference fragments using fragment IDs (or fragIds), and objects using database IDs (or dbIds).

objects representing logical, selectable entities that can have properties attached to them.fragments representing individual meshes with properties like transform matrices, bounding boxes, or materials.When Model Derivative service translates your 2D or 3D designs for Forge Viewer, the output includes, among other things: Note: some of the code samples below use not-exactly-public APIs (typically the classes and functions under namespace, and methods and properties under viewer.impl) which are subject to change.īefore we look at the individual tasks, let's clarify two important terms: fragments and objects. Let's take a look at how these tasks can be implemented for both 3D and 2D models.

When building advanced applications around Forge Viewer, it is often necessary to traverse the hierarchy of model elements, access or manipulate individual geometries, or compute their bounds.

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