Macro Wiring And Hoses

These macros support the creation and maintenance of Wires and Hoses.



Background
As part of our other FreeCAD projects we needed some way to document wiring and hoses. This set of macros was developed to meet that need. There is a lot this system doesn't do, but what it does do is provide visual representation of wiring and hoses, either as an isolated system or with the wiring and hoses in the context of a FreeCAD model. The record of all the wires and hoses is kept in a CSV format file outside of FreeCAD. So the file may be loaded into a spreadsheet program or used by other software.

Description
As part of a documentation project we discovered we needed to document wires and hoses. We tried some different scenarios such as creating lines or cylinders as part of the existing model. Due to either problems using or maintaining it we decided to keep the information in a different format and outside of FreeCAD. That way they could be created on their own or created within an existing document. That decision allowed the user to work with the wiring and hoses in the way which suited them. As well they could work with it in different ways at different times as needs changed.

We initially weren't sure how to maintain a list of the hoses and wires and various different approaches were tried. The easiest way seemed to be to use the CSV file format which has been around for a long time. Also there were routines already written for managing CSV files from Python. Some of the advantages were: The next decisions were "how" to define such cables runs. As our purpose was primarily documentation, we chose to run line segments from point to point. Issues such as turn radius are not dealt with. Also cable diameter is not handled. A table of the cable runs is maintained through the CSV file but such things as proximity of cables (for electrical interference issues) and run length are not supported (although it might be possible to add a rudimentary cable run length quite easliy).
 * human readable
 * can be loaded into any spreadsheet
 * can be maintained using a spreadsheet or simple text editor
 * a possible future enhancement would be to use it with the FreeCAD spreadsheet workbench

This set of macros is essentially a "proof of concept", it demonstrates some ideas and their feasibility. Our main goal was documentation, not physical plant management.We decided to maintain a data structure of points, which are the points through which the wires and hoses run. Secondly we set up a data structure which defines the cables and hoses in terms of the points they pass through. So a wire may only be routed where points for it have been defined.

For the 2 data structures we chose the following names:
 * Nexus - a point through which a cable or hose may pass (the plural is Nexi). Nexi are simply points in 3-space, for ease of visualisation the software places toroid rings around the location but this is only for ease of use. The toroid rings can be toggled off or on depending on user preference
 * Flows - generically these are routes comprised of Nexi. A code is associated with each type, the default codes being
 * W - electrical wires
 * C - conduits, intended primarily for wires but able to contain anything
 * H - hoses to carry a variety of liquids
 * G - gas lines
 * K - a camera routing, this is really just reserved for future exploration as per Tour camera animation

Both Nexi and Flows have user assigned names, in addition Nexi have internally assigned IDs to facilitate management. Being points or locations in 3-space Nexi do not have colours but Flows can have one of 48 defined colours. The emphasis on colours ties back to the intended purpose being one of documentation.

The general workflow is
 * define and position Nexi
 * define Flow(s) in term of Nexi
 * for maintenance purposes edit both Nexi and Flows either visually using the FreeCAD GUI or using a tabular approach and the CSV definitions

As the data file which holds both the Nexi and Flow definition is text based it can be used in any text editor or by any other program wishing to access the data.

Installation
The code for Wiring And Hoses is in multiple macros and a library. So installation is comprised of copying the code to the appropriate Macro directory and invoking the Build Utility from the Macro menu, the Python console or a toolbar button (the preferred method).


 * see Macro_Install_HowTo for information on how to install this macro code
 * see Customize_ToolsBar for information how to install as a button on a toolbar

Usage
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