Street and intersection shape UV

UV coordinates are generated for each shape. They can be used for UV Splits and texturing. Up to three UV sets are supplied for each shape to describe different surface parameterizations.

An example of generated UV coordinates for street, intersection, and lot shapes is shown.

Street shape UVs

A street is composed of three parts: the left sidewalk, right sidewalk (defined relative to the segment’s forward direction), and the central roadbed. Each of these parts can contain one or more shapes, called lanes. Every lane has three sets of UV coordinates.

Street segment with two lanes in the left sidewalk (red), three lanes in the roadbed (green), and one lane in the right sidewalk (blue).

Note:

The copyUV operation enables copying UV sets to other channels, allowing UV set 1 or 2 to be used for texturing.

Roadbed and sidewalk shapes UV set 0

UV set 0 defines a parametrization in which each lane is normalized such that the U-coordinate spans from 0 to 1 along the lane's longitudinal (lengthwise) axis. The V-coordinate spans from 0 to 1 across its lateral (widthwise) axis.

UV set 0 on a street segment consisting of one lane on each sidewalk (left and right) and three roadbed lanes.

Note:

When opening scenes that were created in CityEngine 2024.1 or earlier, the street shape is converted into a lane shape. Additionally, a laneWidth object attribute is automatically added to each street segment. This attribute specifies the lane width used for generating lanes using the UVs that are consistent with the behavior in CityEngine 2024.1 or earlier. This functionality is only supported when there is a single roadbed lane.

Roadbed and sidewalk shapes UV set 1 and 2

UV sets 1 and 2 encode distance fields in meters along and across each lane. In both sets, the U-channel represents the longitudinal distance: in set 1, from the start to the end of the segment; in set 2, from the end back to the start. The V-channel in both sets represents the lateral distance across the part, enabling continuous texture mapping.

UV set 1 on roadbed lanes

UV set 2 on roadbed lanes

Note:

The texture is continuous across the lanes.

Intersection UVs

Intersection shapes use the same UV set 0 parameterization as lanes on a segment. In general, intersection shapes do not have other UV sets, except for the FreewayEntry shapes.

Freeway entries

Freeway entries supply a UV set 1 to identify the inside edge shape that adjoins another street shape. The V = 0 edge is always on the inside of the freeway intersection.

Freeway entries