# Python Solution to Dimension Tracking

# The Problem

To make FreeCad work you often need to enter values of various dimensions. There does not seem to be a method internal to FreeCad ( and probably there should not be ). These dimensions come from various sources:

- Spec. sheets.
- Measurements
- Calculations
- Design decisions.

You more or less need some notes to keep track of this stuff. Some of this may be paper sketches, paper notes, and digital documents ( many may choose spreadsheets ). I find spreadsheets to be very error prone so I looked for a python solution. The very simple version of this is shown in: FreeCad Gear Box This has now evolved, and this document will describe the solution. For the actual code contact: User:Russ_hensel

# A Python Solution

My Python solution consists of a set of interacting classes:

## PartDimension

This class holds a single dimension. Of course you can just go: a_dimention = 22. What is wrong with that? This dimension has a name and a value. What it does not have is units or a type that may help distinguish between pure numbers ( teethe on a gear ), angles, and linear dimensions. Also I have upgraded the class so that it does easy unit conversions and is easy to print.

Here is what you might get when you print a PartDimension

print a_dimension output: bolt_sep ( mm ) = 25.0