A collection is a list, with a depth of 1, containing points, polylines and/or polygons. It cannot contain positions. An entity can belong to multiple collections.
| Description | Example |
|---|---|
| Workflow of making a collection |  |
| Representation of a collection in the 3D Viewer |  |
| Representation of a collection in the Attribute Table |  |
When clicking on the collection row, e.g co0, in the [Attribute Table](chapter_1_mobius_interface/3D_view.md), the selected collection will be highlighted in blue in the [3D Viewer](..\chapter_1_mobius_interface/3D_view.md).
#### Modify Collection
##### Method 1
make.Collection function also allows users to add new entities to an existing collection (parent collection), by creating a new collection under the existing collection.
| Description | Example |
|---|---|
| Workflow of adding entities to a collection |  |
| Representation of the updated collection in the 3D Viewer |  |
##### Method 2
Using modify.Collection users can add or remove entities from an existing collection, or add one collection to another collection (parent collection).
| Description | Example |
|---|---|
| Workflow of adding entities to a collection |  |
| Representation of the updated collection in the 3D Viewer |  The new collection now includes the polygon (pgon) and its new extrusion (ex). Polylines are highlighted in red when selected. |