Graphics file

Store your model's 3D geometry data in the graphics.scz file. The structure of your graphics.scz file may differ for your specific CAD application, as a result, this guide does not define a strict data structure but gives guidance on how to generate it with reference to how it applies to the Revit application.

HOOPs node tree structure

Store model elements nodes under model file nodes.

Note: An exceptions to this rule is if an element is grouped by another element or if an element is a member or component of another element.

Use the following HOOPs model tree structure:

• Models
  • Model
    • Model file node
      • Model element 1 node
      • Model element 2 node
      • ...

Figure: HOOPs model tree structure

Callout	Descriptions
A	Model file node
B	Model element nodes

Element attributes

Each element node has the following properties:

• Name: To construct the element node's name, concatenate the element's category name with the element's id within parentheses: Category(element-id). For example, a wall with a Revit ID of 12345 will have the following node name: Walls(12345)
• PersistentID: The element’s BIMPK id, which is the integer id you give the object in "objects.id" in objects.json
• INV_Desc: A description of the element, which includes the element’s Category, Family, and Type data in the following format: Category>Family:Type

For a complete example, see the following Revit wall element attributes:

{
  "Name": "Walls(67890)",
  "PersistentID": "44",
  "INV_Desc": "Walls>Wall:Interior Partition Wall"
}

Figure: Node element attributes

Callout	Descriptions
A	Node element
B	Node element properties

Rooms and spaces

Visibility

Rooms and Spaces usually have transparent geometry and are set to hidden by default. To view them in the platform viewer, set them to visible.

GenericType

Room and space element nodes require special handling by the platform viewer. To indicate that an element is a room or space, set GenericType of the Room/Space’s node to a value of BIM_Space.

Note: GenericType is a built-in attribute of a HOOPs node and its value is empty by default.

Figure: Room invisibility

Callout	Descriptions
A	Node element
B	Node element properties

Nesting related child model elements

Nest related child model element nodes under the parent model group node in the node tree.

For more information, see the following node structure of a Revit wall element and its component related items:

Figure: Nested related child nodes

Callout	Descriptions
A	Parent model group node
B	Nested related child nodes

Example case

In Revit, a Curtain Wall doesn’t have any geometry by itself so if you do not nest Panels and Mullions, when a user select the Curtain Wall element in the viewer, no geometry is highlighted.

Model file Hash Code

A hash code is a property that the your application generates and adds to the first Model File node to identify the HOOPs file. For now, the value sets to ‘123456780’.

Figure: Model file hash code

Callout	Descriptions
A	Model file
B	Hash code