The Start Direction is set by default to Auto Detect, in which the direction of travel is based upon the orientation of the vehicle relative to the starting vertex of the polyline. You can select Forward or Reverse to force the direction of travel. The Keep Current setting continues in the current direction, which works well when using Follow Drive after maneuvers performed in a different drive mode.
The Start Position Automatic setting has the vehicle positioned at the end of the selected line closest to the point you picked with the steered wheels and all spines aligned tangentially to the line. If you want to adjust the vehicle orientation set Start Position to Manual. Start Position cannot be edited if the path is pre-selected; in these cases, the current vehicle position and orientation is used.
By default Follow Drive generates a non-editable path; you can move or rotate the entire path but not adjust the alignment. This gives the best results in most cases. If you wish to create a path with a series of target points that can be dynamically edited, select Generate An Editable Path.
If you opt for an editable path you can select one of two line-following algorithms:
- In the Split Lines Into Lengths Of option, Autodesk Vehicle Tracking follows the line as closely as possible, and this is easier with a short segment length. The default length of 2.5 m should be suitable for most situations. With a much shorter length, the program runs slower.
- In the Track Vertices Only option, Vehicle Tracking uses the vertices as target points. Note that this option follows the automatically generated vertices on splined polylines.
Three optimizations are available:
- Ignore Vertices Closer Than, with a suitable distance, is a recommended option, to allow Vehicle Tracking to ignore closely spaced vertices. Lines can be difficult to follow if they contain many closely spaced points.
- Follow Line As Closely As Possible allows the vehicle to wander from the line temporarily instead of stopping if it cannot reach target points on a tight bend. The vehicle ignores target points that it cannot reach and focuses on the next one. This has the effect of allowing the vehicle to drift out on tight bends.
- Optimize Resulting Path By Removing Unnecessary Target Points allows Vehicle Tracking to remove targets points at which no steering changes are required.