Learn CityEngine terminology.
Attribute—In CityEngine, an attribute refers to a global variable defined in rule files that gives information to describe objects. You can modify attribute values in the Inspector or directly in the rule file in the CGA Editor. Object attributes can also be defined in a feature class attribute table outside of CityEngine in ArcGIS Online or ArcGIS Enterprise.
CGA—Computer Generated Architecture (CGA) shape grammar is a unique programming language used in procedural modeling to generate 3D models. You create a CGA rule file from a series of rules and provide more detail as you add more rules. You can assign CGA rules to shapes, such as a street lot or a building footprint.
Graph network—A graph network is a group of linear features in an urban setting such as streets, walls, or railways. Streets include blocks, building lots, and the spaces in between theses features.
Layer—A mechanism to display geographic datasets in CityEngine. When you add or create a dataset, it is added to one of the following layer types:
- Shape Layer contains shapes, typically used as building footprints for the generation of CGA models.
- Graph Layer contains graph networks and blocks, dynamic shapes (street shapes, building footprints), and generated models.
- Static Model Layer contains static models, such as COLLADA files.
- Map Layer contains arbitrary maps (images) and can be used to globally control various parameters for scene objects. The scene terrain is also created using a map layer.
- Analysis Layer contains visibility analyses objects, such as viewsheds that display surfaces and structures that are visible and hidden from a given observer.
Layout—A CityEngine layout contains a series of windows arranged on your screen that you can customize for each of your projects. All windows are dockable and can be dragged to any location in the layout. A typical CityEngine layout displays the Scene Editor, Navigator, CGA Editor, Viewport, Inspector, and Dashboards.
Level of detail (LOD)—The complexity of an 3D model or object. An example of a low LOD model is a building footprint as an extruded polygon. A higher LOD model can contain textures, windows and doors, roofs, and interior features. Often CityEngine reduces the LOD as it gets further away from the viewer. Reductions in LOD may involve generalizing textures applied to features or simplification of their geometry. Reducing feature complexity and detail improves rendering performance by decreasing the workload on the graphics pipeline.
Model—The representation of any 3D object, stored as a digital collection of features, rules, or both, and can be displayed as a 3D image through rendering. 3D models are used extensively in the world of computer graphics, such as in film making, architecture, engineering, computer gaming, and urban planning. 3D models can range from a simple cube to a complex 3D model with higher LOD. In addition, 3D models can be generated from a variety of other sources, such as 3D scanning (lidar, sonar, and so forth), or derived from analysis procedures. COLLADA is an example of a 3D modeling format commonly used today.
Portal—A connection to CityEngine from ArcGIS Online or ArcGIS Enterprise. In CityEngine, you sign in to a portal to share your work and access content shared by others.
Project—A collection of resources organized in your workspace. A project consists of assets, data, images, rules, scenes, and other resources. Projects are collected in workspaces that are set when you start CityEngine for the first time. You can reference and include items from your organization's portal.
Rule—A user-defined syntax language that allows you to define behaviors related to the attributes and geometry of a feature. They are used to enhance the editing experience and help enforce data integrity. Rules are added upon each other to iteratively create CGA rules.
Scene—A CityEngine scene is a 3D representation of geospatial content that allows you to visualize and analyze geographic information in an intuitive and interactive 3D environment. As you interact with the data in the scene, you gain an understanding of the 3D world of the scene. You organize the scene data in groups and layers and display this data based on rules and attributes.
Shape—The main input for procedural modeling with CGA rules. CGA rules operate on shapes, such as building footprints and need a shape to apply the start rule. Through CGA operations, shapes are modified and result in model geometry. Geometrically speaking, shapes are polygons. They can be drawn manually or imported from external sources.
Static model—Geometrical models imported into CityEngine that cannot be modified. They are only positioned and scaled. The data is read-only and can be generated with 3D design tools.
Viewport—The viewport is the main interaction tool with scenes and is the primary work area in CityEngine. The viewport provides a visualization of your layers, data, and objects. You can have any number of open viewports with different camera views, such as a top view and 3D view. Only one viewport is active at any given time.
Workspace—The central hub for the location of your files. Navigator is a tool that allows you to navigate and manage the workspace. The Navigator provides options for creating, navigating, and manipulating files and folders in the workspace. You set the location of your workspace when you start CityEngine for the first time.