## 2 Generative CAD Model
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**No.** & **Parameter Name** & **Index** & \
\begin{tabular}{c} **Type/CATIA** \\ **Module** \\ \end{tabular} & **Relation** &
\begin{tabular}{c} **Initial Value** \\ **mm** \\ \end{tabular} \\ \hline \hline \multicolumn{6}{c}{Tree of external fixation device} \\ \hline
1. &
\begin{tabular}{c} Outer tree \\ diameter \\ \end{tabular} & \(\text{d}_{\text{s}}\) & Independent/Sketcher & - & 12 \\ \hline
2. & Tree wall thickness & \(\delta\) & Independent/Sketcher & - & 1.5 \\ \hline
3. & Tree length & \(\text{L}_{\text{s}}\) & Constant/Sketcher & - & 320 \\ \hline
4. &
\begin{tabular}{c} Length of chamfer \\ for tree and \\ coupling mount \\ \end{tabular} & c & Depended/Part & c = \(\delta\) & 1.5 \\ \hline \hline \multicolumn{6}{c}{Clamping plates} \\ \hline
5. &
\begin{tabular}{c} Basic thickness of \\ clamping plates \\ \end{tabular} & \(\delta_{\text{op}}\) & Independent/Part & - & 3 \\ \hline
6. &
\begin{tabular}{c} Distance between \\ axis of half pin and \\ clamping plate. \\ \end{tabular} & z & Constant/Sketcher & - & 1 \\ \hline
7. &
\begin{tabular}{c} Radius of \\ curvature of the \\ groove on the \\ clamping plate \\ \end{tabular} & r\({}_{\text{pk}}\) & Depended/Sketcher & r\({}_{\text{pk}}=(\text{d}_{\text{k}}+1)/2\) & 3 \\ \hline
8. &
\begin{tabular}{c} Total thickness of \\ clamping plate \\ \end{tabular} & \(\delta_{\text{pl}}\) & Depended/Part & \(\delta_{\text{pl}}=r_{\text{pk}}-z+\delta_{\text{op}}\) & 5 \\ \hline
9. &
\begin{tabular}{c} Diameter of hole \\ on clamping plate \\ and clamping ring \\ \end{tabular} & d\({}_{\text{N}}\) & Depended/Sketcher & d\({}_{\text{N}}=\text{d}_{\text{n}}\) & 8 \\ \hline
10. &
\begin{tabular}{c} Distance between \\ grows for half pins \\ on clamping plate \\ \end{tabular} & L\({}_{\text{pk}}\) & Constant/Sketcher & - & 23 \\ \hline
11. &
\begin{tabular}{c} Radius of file on \\ clamping plate \\ \end{tabular} & a & Depended/Sketcher & a = (L\({}_{\text{pk}}\)/2) + 5.5 mm & 17 \\ \hline
12. &
\begin{tabular}{c} Width of clamping \\ plate \\ \end{tabular} & b & Depended/Part & b = a & 17 \\ \hline \hline \multicolumn{6}{c}{coupling/coupling mount} \\ \hline
13. &
\begin{tabular}{c} Diameter of hole \\ on coupling and \\ coupling mount \\ \end{tabular} & d\({}_{\text{p}}\) & Depended/Sketche & d\({}_{\text{p}}=\text{d}_{\text{s}}\) & 12 \\ \hline
14. &
\begin{tabular}{c} Diameter of central \\ part of coupling, \\ coupling mount \\ and hole in \\ clamping ring \\ \end{tabular} & d\({}_{\text{t}}\) & Depended/Sketcher & d\({}_{\text{t}}=\text{d}_{\text{s}}+2\delta\) & 15 \\ \hline
15. &
\begin{tabular}{c} Length of central \\ part of coupling \\ and coupling \\ mount \\ \end{tabular} & l\({}_{\text{c}}\) & Depended/Sketcher & l\({}_{\text{c}}=\text{d}_{\text{s}}+2\) mm & 14 \\ \hline
16. &
\begin{tabular}{c} Screw length on \\ coupling and \\ coupling mount \\ from the side of \\ coupling ring \\ \end{tabular} & l\({}_{\text{nc}}\) & Depended/Sketcher & l\({}_{\text{nc}}=\text{h}_{\text{n}}+4\) mm & 10.8 \\ \hline \end{tabular}
\end{table} 
Table 1: External parameters of sub algorithms for components design of external fixation device. After the parameters are defined in the skeleton model, they are published and used as external parameters during the phase of the definition of the shape of external fixation device, and during the definition of position for some of the components of the external fixation device. Relationships inside the skeleton model give flexibility to the design to change the shape, place, and orientation of external fixation device components. Relationships reference design parameters and geometrical elements, which are used to place the components of the external fixation device with correlation to the main coordinate system of skeleton model. Except parameters and relationships, the skeleton model was inside all other referent elements, such as points, planes, and axes (Figure 2).