The draw tool is used to create infrastructure pathways on the current Layer.
- Click once on the map to draw a point
- If you have a point already selected, then clicking on another point will draw a line between them. Clicking on the map will draw a new point with a line connecting them.
- As you draw, curves will be automatically generated according to the properties of the active layer's LayerType.
- Clicking on a point will allow you to edit its properties in the Tool Properties panel.
- Clicking on a line will put a point which will always be constrained to that line. Note that this can be changed by selecting the point and then un-checking "Snap to line" in its properties
- Click-dragging on a line will insert a new point that not snapped to the line, and then move it to the location you drag to.
With the draw tool, you may also select and move individual points, similar to the Select tool, 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 diffrent curves by setting selecting their points and setting additional constraints, as in the video above.