The draw tool is used to create infrastructure pathways on the current Layer.
Click once on any part of the map to add a control point. Connecting lines will be added automatically between additional control points. Curves will generated automatically according to the properties of the active layer's LayerType.
Stations can be linked by using the draw tool to select each one in succession.
Clicking within an existing line will add an additional constraint point. By default, this point will be constrained to its line. It can be unconstrained by un-checking "snap to line" in its properties.
- Click-dragging on a line will insert a new point not snapped to that line. You can then move the point to any location.
Note: constraint points can only be added to straight control lines and not paths (curved lines) generated by the application
With the draw tool (as with the Select tool), you may also select and move individual points, by dragging them around.
Note that depending on the LayerType of the current layer, you may not always be able to connect two points together. (For example: Personal Rapid Transit systems only allow merges and diverges with a maximum of two inbound or two outbound connections.)
Understanding parametric constraints
The Draw tool generates curves with constraints-based parametric modelling, which unifies planning and engineering concerns. It applies the following rules, in order of priority:
- All curves must be tangent to their defining lines
- The track must be as fast as possible (since transport planners generally want speed)
- The track must be as straight as possible (since curves are more expensive to engineer)
Often, these automatic curves are exactly what you want. When they're not, you can make different curves by setting selecting their points and setting additional constraints, as in the video above.