Push and pull shapes

Extrude 2D shapes and modify existing 3D extrusions with the Push Pull tool . You can hover over any shape to display handles to extrude an edge or face.

To extrude a shape, do one of the following:

• Click the Push Pull tool .
• Press P.
• Click Shapes > Push Pull Tool in the CityEngine main menu to open the tool.

Extrude face

Depending on the shape, different arrows appear. This allows you to create shapes along different directions. Hover over a direction arrow for immediate feedback. There are four types of directions, each with a unique color and mouse icon.

Global axes
Face normal
Face normal projected on the ground plane
Special edge directions from adjacent faces

Force new edges

Turn on Force New Edges in the Push Pull tool options or press Ctrl to force the creation of new edges when extruding.

Object before creating a new edge

New edge created during extrusion

Special edge direction

When dragging along the special edge direction arrow, all edges are extended along their adjacent faces during dragging. The arrow appears with a slight offset when it has the same direction as another arrow. The table below shows the difference between the up and special edge direction dragging.

Starting shape.
Shape is dragged directly up along the green arrow.
Shape is dragged along blue arrow extending adjacent faces.

3D edge move

Hover over edges with the Push Pull tool to display edge handles. Similar to dragging faces, you can drag edges in multiple directions.

Edge move along global axis
Edge move along adjacent faces
Edge move along average face normal

While moving the edges with the Push Pull tool, connected faces update to maintain planarity. In addition, the moved edge is intersected with neighboring polygons. Both features are useful for creating roofs as shown below.

The edge before moving the orthogonal faces is shown.

The orthogonal faces moving with the edge are shown.

An inset edge along a roof is shown.

An edge move along the blue axis insets the edge along the existing roof.

3D shape editing

3D shapes allow polygonal editing, such as snapping, splitting, and automatic closing. Split parts can be moved to further refine the 3D shape.

Preliminary split
3D move
Final split and 3D move

Snapping

You can snap to edges or faces within the same shape. You can also snap to guides.

Snap to faces

The following image shows the top face snapping to the bottom face of the same shape:

Snap to edges

You can snap to edges within the same shape.

Snap to a coincidental edge.
Snap to an edge when its perpendicular to the opposite edge.

Snap to guides

You can use guides to snap to when extruding a shape, such as when creating another building with the same height as an existing building.

A guide set to the height of an existing building shape.
The extruded building shape snaps to the guide and is now the same height.

Tool options

The Push Pull tool options include the following:

Push Pull
Distance (m)	Distance in meters of the edge or face extrusion. You can enter a value to lock the extrusion distance along the available directions. Click again to start a new extrusion.
Snapping	Turn snapping options on and off. Extrude a face and snap to faces, edges, or vertices of the same shape. Also snap to guides. Extrude an edge and snap to vertices of the same shape. Press Shift to temporarily enable or disable snapping.
Force New Edges	Force the creation of a new edge when extruding. Press Ctrl to temporarily turn on or off the creation of new edges.