Outline
The cross-section of the tunnel tube and all vehicle areas are defined by their outline geometry.
You can use straight lines, circular arcs and circles to draw these outlines. A valid outline must consist of a single closed curve without intersections. Various catch modes may help you drawing an unbroken outline.
![](../../../../../images/winprop/user_guide/wallman_tuman/tuman_usage/outlines_valid_invalid.png)
Figure 1. Examples of valid outlines (top row) and invalid outlines (bottom row).