# Add Track Tool

This tool is used to add tracks to the model. There are several ways to create tracks described below.

This tool has some different modes and guess which one you most likely want to use depending on what's selected when the tool is activated.

## Main Line

This mode is used to create a continuous line by defining nodes. Curves with customizable radius and curvature change rate are automatically added at corners. This mode is preselected when the tool is activated without any tracks being selected.

Click in viewport to add a node. Click existing track to connect to it.

Press enter or double click viewport to add track(s).

Transition curves are used to gradually change the centripetal acceleration and reduce jerk when entering or leaving a curve. A cubic parabola, y=kx3 is used to calculate the transition curves. This means the curvature changes proportionally to the length projected to a straight line by k or ΔCurvature. Assuming curvature is proportional to arc length (Euler spiral) instead of projected length (Cubic function) the formula Jerk/V3 can be used to calculate k.

## Junction

This mode is used to create new tracks from scratch. All these tracks fit in skew grid defined by center distance and angle. 'Matching Straight' is the default formation.

Click in viewport or press enter to add track(s). Click existing track to connect to it.

Press tab to change what end you are placing (useful for asymmetric tracks like curves).

Press arrow keys to make track go along a model axis or hover an existing track to make new track parallel to it.

## Library

This mode is used to add pre-defined track formations, such as a station or a turntable.

Behaves similar to Junction mode.

## Copy

This mode is used to copy one or more existing tracks. These copies can be attached to any existing tracks. This mode is in most cases preselected when activating the tool with selected tracks.

Behaves similar to Junction mode.

Requires at least one selected track.

## Offset

This mode is used to offset tracks, e.g. to make a double track.

Click in viewport, press enter or type in length and press enter to add track(s).

Requires selected tracks to all be connected and not be connected and not branch out.

## Connect Ends

This mode is used to form a quadratic Bezier curved track connecting 2 loose track ends. This mode is preselected when activating the tool with 2 selected tracks that aren't connected to each other.

Click in viewport or press enter to add track(s).

Press tab to toggle possible tracks to insert.

Requires at least 2 loose track ends in selection.

Copyright © Julia Christina Eneroth 2015.