Remarks

This operator generates 3-dimensional corridor meshes from line features. The operator accepts only line geometries, other features will be passed along up the operator chain. You can specify one of four types of cross section: rectangle, trough, circle and custom.

You can use a constant type of cross section for your CorridorOperator3D, or you can let the type depend on a feature attribute by using a KeyedAttributeVariable<CrossSection> for the CrossSection property. Feature attributes can also be used to control the shape of cross sections, for example the width and height of a rectangle.

The corridor mesh can be visualized using an ordinary MeshVisualizer. Edges can be activated using GenerateJoinEdges and GenerateSegmentEdges properties and are visualized using a LineVisualizer.

Cross section types

Each of the four cross section types is derived from an abstract base type.

Cross section name	Shape
CustomCrossSection
RectangleCrossSection
TroughCrossSection
CircleCrossSection

Texturization

A corridor mesh built with any cross section can be textured with a Material attached to a MeshVisualizer. The exact mapping of the U coordinate depends on the cross section type, but generally the first vertex encountered from traversing clockwise from above the corridor is mapped at 0 and the mapping increases clockwise around the cross section ending at 1 returning at the starting vertex. The V coordinate is mapped at 0 at the start of the corridor and at 1 on a distance in meters from the start defined by the TextureScaleFactorV property. The texture is repeated along the V axis until the end of the corridor.

Edge emphasis

Geometrically, the corridor will consist of plane quadrilaterals. The edges between them can be divided into two groups:

• Join edges go around the corridor at each node of the input line.

• Segment edges go along the corridor, parallel to each segment of the input line.

You may want more or less emphasis on the edges in the visualization. The emphasis can be controlled separately for join edges and segment edges via four boolean properties GenerateJoinEdges, GenerateSegmentEdges, SmoothJoins and SmoothSegments. When explicit join edges or segment edges are generated, they can be displayed with a LineVisualizer. When smoothness is turned on, the effects of lighting will be smoothed over the edges (although the silhouette of the corridor will remain angular). You can combine these settings into three degrees of edge emphasis:

• For minimal emphasis, you should turn on the smoothness and turn off the edge generation.

• For medium emphasis, you should turn off both smoothness and edge generation.

• For maximal emphasis, you should turn off the smoothness and turn on edge generation.

There is of course also a fourth option: to use both smoothness and edge generation, but it is probably seldom desirable.