The Cable Length tool provides you the estimated length of cable each camera will require. The tool also groups the cables into the standardised cable lengths available for purchase, and provides an estimate on how many of each length you need.
To use the cable tool, select the Cable Lengths button from the main inspector, or via selecting the server rack object present in the scene.
The Cable Length tool uses the 3D model of the server rack as the destination to estimate where the end of the cables will be. TVA calculates the cable drop at the corner of the truss closest to the server rack. You can move the server rack to replicate the distance the cables need to travel by clicking on the server rack model in the 3D scene, and adjusting it's position using the transform tool [w].
There is currently a cautionary 2m length added to the path to handle any real-world routing.
You can hover a camera in the cable length list to view the calculated path taken that resulted in the listed cable length.
This path finds the closest corner (whether or not an upright is present there) to the server rack object, and attempts to get the shortest path to the camera.