Before using Linear Draft it is recommended that two files are prepared.
- A blank 3D seed file - that has correct levels and level symbology loaded, and
- A track alignment file - this is to be referenced into your seed file and should be made up of complex strings that represent a minimum of two tracks
A typical file showing markers and track alignment is shown below:
Markers can be placed in one of two ways:
- Manually draw circles in your seed file at locations where you intend to place structures
- Reference in a marker file with the markers already drawn where structures are to be placed.
For performance optimisation it is recommended that models designed using Linear Draft should be no longer than a catenary wire tension length (including overlaps).