010] CityEngine Layer Types Explained (Graph, Shape, Map & More)

This is a beginner-friendly guide to understanding CityEngine layer types. In this tutorial, you will explore the 10 distinct layer types in Esri CityEngine. Understanding how to categorize data into Graphs, Shapes, Static Models, and Maps is the most crucial step for maintaining an organized and efficient 3D urban modeling workflow.

CityEngine fundamentally categorizes object properties into five main layer types. Since the 'Map Layer' is further subdivided into five specific functions, there are a total of 10 layer types you can utilize.

We will only do a broad overview today. For highly technical details on each layer, it is always best to refer to the official CityEngine Help documentation.

When you import a specific file, CityEngine automatically reads its geometric properties and generates the appropriate layer. You can also create these layers manually from the top menu.

Lines → Graph Layer
Faces/Polygons → Shape Layer
3D Objects → Static Model Layer
Image Files → Map Layer

The Analysis Layer is an exception; it is not created by importing a file, but rather automatically generated when you perform tools like Viewshed Analysis.

[img 1 : Context menu in the Scene panel showing options to create new Graph, Shape, Static Model, Analysis, and Map layers]

Scene panel

Any newly created layer is immediately registered and visible in the Scene panel. Let's look at them one by one.

1. CityEngine Graph Layers (Street Networks)

If you select the Street Creation tool and draw a simple triangular road network, you will see a Streetnetwork layer appear in your Scene panel.

[img 2 : Scene panel displaying a generated Streetnetwork layer containing Major Edges and Nodes]

This layer tells you exactly how many elements it contains. Notice the Blocks sub-layer? These are the parcels (lots) automatically generated within the enclosed space of the roads. You can disable this auto-generation if needed, as real-world parcel divisions rarely look like these perfectly theoretical shapes.

When drawing manually, it is named Streetnetwork. If you import a line-based file (like a road centerline CAD or SHP), it creates a Graph Network layer. They are fundamentally the exact same type of layer; the name just differentiates whether it was hand-drawn or imported.

When importing external networks, I highly recommend using SHP files over CAD. CAD files often require extensive layer filtering and cleanup.

[img 3 : Scene panel showing an imported Graph Network Road_Line layer with hundreds of objects]

When you import a centerline SHP, CityEngine builds the default road geometry automatically. You will need to tweak the parameters to match your actual design, but the true power of SHP files is that you can bake data (like street width or sidewalk width) directly into the GIS attributes, allowing the 3D road to generate perfectly instantly.

💡 Practical Tip: Always clean your polylines before importing them into a Graph Layer. Overlapping lines or tiny duplicate segments from raw CAD files will cause CityEngine to generate broken intersections and erratic blocks.

2. CityEngine Shape Layers (Polygons)

Shape Drawing tool

If you select the Shape Drawing tool and sketch a polygon, a New Shapes layer is generated.

[img 4 : Scene panel displaying a New Shapes layer generated by the polygon drawing tool]

This layer acts as the primary foundation for your CGA rules. Buildings, footprints, and zoning areas all reside here.

3. CityEngine Static Model Layers (3D Objects)

This layer is created when you import pre-built 3D objects from external software. CityEngine supports common 3D formats like OBJ, DAE, KML, and FBX.

[img 5 : Scene panel showing an imported sphere object inside a Static Model Layer]

You cannot apply CGA rules to a Static Model to change its fundamental geometry, but you can use them as assets (like custom trees or benches) inserted by your CGA rules.

4. CityEngine Analysis Layers

As we saw in the previous lecture, the Analysis Layer is automatically generated when you execute a spatial analysis, such as the Viewshed Creation tool.

[img 6 : Scene panel showing an Analyses layer containing a Viewshed object]

5. CityEngine Map Layers (Images and Terrain)

Map Layers are incredibly versatile and come in five sub-types:

[img 7 : Dialog box showing the 5 types of Map Layers: Texture, Obstacle, Mapping, Terrain, and Function]

Texture: Imports a georeferenced image (like a satellite map) to drape over the ground.
Obstacle: Reads the color values of an image to act as a barrier, preventing automatic street generation in specific areas.
Mapping: Reads image color values to drive specific parameters in your CGA rules (e.g., making buildings taller in darker areas of a heatmap).
Function: A specialized mathematical mapping tool (very rarely used in standard architectural workflows).
Terrain: Imports Digital Elevation Models (DEM) to generate 3D topography. This is the most frequently used Map Layer in practical workflows.

Moving and Pasting Objects Between Layers

Sometimes you need to split a large layer by cutting out a few objects and moving them elsewhere.

[img 8 : Context menu demonstrating the Cut option for selected shapes in the Scene panel]

The process is simple: select the objects, Cut (Ctrl+X) or Copy (Ctrl+C), right-click an empty space in the Scene panel, and select Paste (Ctrl+V).

[img 9 : Pasting the cut objects into an empty space to automatically generate a new matching layer]

[img 9-2 : Pasting the cut objects into an empty space to automatically generate a new matching layer]

A new layer of the corresponding type will automatically be created to house the pasted objects. Alternatively, you can select an existing layer of the same type and paste the objects directly into it. You cannot paste objects into a mismatched layer type (e.g., you cannot put a Shape into a Graph layer).

The Missing Link: What About "Point" Layers?

Looking at these categories, you might feel like something is missing.

What about Points?

CityEngine does not have a dedicated Point Layer. You can only import point data via SHP files. But when you do, it doesn't go into a Graph Layer as you might expect.

[img 10 : Imported point shapefile rendering as a Shape Layer in the Scene panel]

If you import a point SHP file, it registers as a Shape Layer. Why? Let's zoom in closely on one of those "points" in the 3D View.

[img 11 : Zoomed-in view showing that a point is actually converted into a 10cm by 10cm square polygon]

Yes, that's right. CityEngine automatically converts a 0-dimensional point into a tiny 10cm x 10cm square polygon. Because it now possesses surface area, CityEngine assigns it to a Shape Layer.

💡 Practical Tip: Since points become tiny flat polygons, they are perfect for placing individual assets like trees or streetlights. Just write a simple CGA rule that inserts your desired 3D object onto that shape, and you have instantly populated your scene!

Organizing with Layer Groups

As your city grows, your Scene panel will become cluttered. You need to group layers together.

[img 12 : Right-click menu showing the New Layer Group option]

Right-click an empty area in the Scene panel and select New Layer Group.

[img 13 : Dragging and dropping existing layers into the newly created Layer Group]

Simply drag and drop the desired layers into this new folder icon to keep your workspace tidy.

Quick Toggles: Visibility, Color, and Lock

Finally, look at the checkboxes to the right of each layer name. They are incredibly useful for quick scene management.

[img 14 : Diagram pointing out the Color Override, Lock, and Visibility checkboxes next to a layer]

Visibility (Eye icon): Toggles the layer on and off in the 3D View.
Lock (Padlock icon): Prevents accidental selection or modification of the geometry. Excellent for locking down finished terrain.
Color Override (Colored box): Clicking this allows you to apply a uniform color to every object within that layer, temporarily bypassing their individual CGA textures for easy visual distinction.

Now that you understand how to organize the physical layers of your city, it's time to learn how to manage the resources that build it.

Next Steps

In Lecture [011], we will dive into the Navigator Panel, the central hub for managing your scripts, textures, and assets.

To learn how to create and control street networks in CityEngine, see [009] How to Generate Basic Streets in CityEngine

To learn how to manage your project resources effectively, see [011-012] CityEngine Navigator & 3D Viewport Guide (Workspace, Camera & Bookmarks)

[002-003] How to Create Terrain and Align 3D Buildings in Esri CityEngine
To learn how to manage your project resources effectively, see [011-012] CityEngine Navigator & 3D Viewport Guide (Workspace, Camera & Bookmarks)
To control building heights and land use types using 2D image maps, see [108] How to Use Map Layers to Control Rules in CityEngine

If you have any questions, please leave a comment. Let's solve them together!

[A Quiet Thought]

"Downstairs in a small alcove off the lobby, Lynne was thinking about the Egyptian pyramids, medieval cathedrals, British battleships, and the late twentieth-century arms race. 'Were they all part of the same pattern?' she wondered. No matter how much better technology raised per capita income, there were always entities that absorbed the surplus and pushed ordinary people into a lifetime of labor. No matter how much productivity increased, people's work never seemed to decrease. It only changed form. If the workers were not reaping the fruits of their labor, who was? She began to see many things in a way she had never seen them before."
— James P. Hogan, Giants' Star

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