Terminology

The following table lists key terms used in ArcGIS CityEngine:

ArcGIS Urban	ArcGIS Urban and ArcGIS CityEngine provide a collaborative urban planning system for city planners, designers, GIS analysts, and 3D visual artists. ArcGIS CityEngine includes a suite of tools that integrate workflows with ArcGIS Urban such as importing an ArcGIS Urban plan, making changes in ArcGIS CityEngine and saving the changes back to the ArcGIS Urban plan. See the Work with ArcGIS Urban integration tutorial for more information.
Attribute	Rule attributes are global variables defined in CGA rule files that provide information to describe objects. You can modify rule attribute values in the Inspector window or directly in the CGA rule file in the CGA Editor or VCGA Editor. Attributes can also be values describing other objects in the scene, such as object attributes, array attributes, or layer attributes, and can be edited in the Inspector window.
CGA	Computer Generated Architecture (CGA) shape grammar is a unique programming language used in procedural modeling to generate 3D models. A CGA rule file consists of several rules and components such as operations or functions that define how the model is created. You can assign CGA rule files to shapes, such as a lot, block, street lane, or a building footprint. See the Basic shape grammar tutorial for more information.
Dashboard	Dashboards are charts of key numbers that are driven by CGA report values. When you change an attribute of a CGA model using the Inspector window or a model handle, for example, the dashboard is updated automatically and syncs with the 3D model in the Viewport window. See the Rule-based modeling and Reporting tutorials for more information.
ESRI.lib	ESRI.lib is an ArcGIS CityEngine project that contains a library of useful resources, such as CGA rules and assets. It is automatically installed in your ArcGIS CityEngine workspace and can be found in the Navigator window.
Graph network	A graph network is a group of linear shapes in an urban setting such as lanes, walls, or railways. A street graph network can include segments, lots, blocks, nodes, or lanes. See the Terrain and dynamic city layouts tutorial and for more information.
Layer	A mechanism to display geographic datasets in ArcGIS 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 (lane 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. Guide layer—Contains guides created for objects in a scene.
Layout	An ArcGIS 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 ArcGIS CityEngine layout displays the Scene Editor, Navigator, CGA Editor, Viewport, Inspector, and Dashboard windows.
Level of detail (LOD)	The complexity of a 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. 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. See the Basic shape grammar tutorial for more information.
Model	In ArcGIS CityEngine, you can generate models from shapes by applying CGA rules to them. Models can also be imported as static models. You can export them to a variety of 3D formats, such as COLLADA, for use as 3D models in other tools. Models are used regularly in industries such as architecture, engineering, construction, urban planning, and entertainment to visualize and design urban environments. See the drawing or Mass modeling tutorials for more information.
Portal	A portal is an ArcGIS Online or ArcGIS Enterprise server that allows you to share your work and access content shared by others. To connect to a portal server, you must provide the URL and sign in.
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 ArcGIS CityEngine for the first time.
Rule	A user-defined syntax behavior that builds upon the attributes and geometry of a shape. Rules are added upon each other iteratively to create a CGA rule file.
Scenario	Scenarios allow you to create multiple designs within a single scene and compare them. Scenarios can be displayed side by side in viewports for visual comparison. Dashboards are also scenario aware and can show the values for multiple scenarios simultaneously, allowing you to compare the performance of designs against each other.
Scene	An ArcGIS 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.
Shape	Shapes, such as building footprints, are the main input for procedural modeling with CGA rule files. They can be used to generate 3D models. Also, shapes can be drawn manually with the shape creation tools or imported from external data. See the drawing or Basic shape grammar tutorials for more information.
Static model	Static models are models imported into ArcGIS CityEngine that cannot be modified by rules and attributes. They can be modified with the transform tools such as the Transform Move or Rotate tools.
Terrain	The terrain layer is a special map layer that visualizes the elevation of the scene topography using image data. It also serves as reference elevation for align operations for scene objects such as shapes or graph nodes. You can edit existing terrain with the interactive terrain editing tools. See the Terrain and dynamic city layouts tutorial for more information.
Tool options	You can modify the behavior of ArcGIS CityEngine tools using the tool options window for that tool.
Viewport	The Viewport window is the primary work area in ArcGIS CityEngine and main location to interact with scenes. The Viewport window 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.
Visual CGA (VCGA)	Visual CGA (VCGA) allows you to combine CGA rules in a visual node-based editor that simplifies creating procedural designs. It is based on a set of high-level architectural components and materials released with ESRI.lib, designed to support a wide range of massing typologies usable across VCGA, CGA, and urban environments.
Workspace	The ArcGIS CityEngine workspace is the central hub for your project files. You manage your workspace using the Navigator window, which allows you to create, navigate, and modify files and folders. You set the location of your workspace when you start ArcGIS CityEngine for the first time.