# Comparison of CAD Software for Designing Cellular Structures for Additive Manufacturing
## 3 Results
### Altair(r) Sulis(tm)  
Altair(r) Sulis(tm) is a design software for AM that is designed to create complex lattice structures as well as fluid channels. Altair Sulis offers integrated manufacturability analyses and compensation tools to reduce the risk of costly manufacturing errors. Currently, Altair(r) Sulis(tm) is a standalone program, but it will be integrated into the Altair Inspire software in the future. The program can be used to create simple geometries like cuboids and cylinders or modify imported geometries, such as creating a wall or mirroring. Altair(r) Sulis(tm) provides 17 tools under the Lattice tab, which can be divided into three groups as follows: surface lattices (such as TPMS or shell lattice structures), strut lattices, and planar lattices.  
The program is intuitive, and only a few steps are required to fill a geometry with lattice structures. Individual areas can be separated from the rest of the model and defined as a solid. The area to be populated can then be filled using a variety of tools. These include surface-based, strut-based, and planar lattice structures. Within each subset, a number of different unit cell designs can be selected, and parameters such as cell size and strut thickness can be set. Altair(r) Sulis(tm) allows the user to import a variety of file formats. However, the easiest way is to import STL representations of a model. Although the user can manually select areas of interest in the imported model, a more practical approach is to separate the solid model areas from the design space that the lattice will later fill. The example geometry \"helical gear\" was prepared in SolidWorks(r) beforehand to obtain the outer and inner solids as well as the design space in between (see Figure 3). Geometries were set in Sulis(tm) accordingly. The inner and outer volumes were defined as solids, and the inner design space was defined with the exact same settings as in Grasshopper(r) and nTop.  
After the formulation of all parameters, the lattice generation was started, and the results shown in Table 8 were computed as well as measured.  
Figure 11 displays the workflow of the helical gear in Sulis(tm) for the BCC base cell geometry.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Criteria** & **BCC** & **FCC** & **Relative Change** \\ \hline Lattice processing time & 1 min 37 s & 1 min 45 s & 8.2\% \\ Resolution & 0.1 mm & 0.1 mm & \\ Export time & 1 min 11 s & 51 s & 19.6\% \\ File size & 413 MB & 436 MB & 5.6\% \\ \hline \hline \end{tabular}
\end{table}
Table 8: BCC and FCC lattice generation values of the helical gear in Altair® Sulis(tm).  
The imported seat geometry was processed in a similar manner (Figure 12), except for the size of the lattice structure (13 \(\times\) 23 \(\times\) 4).  
The computed as well as the measured results are shown in Table 9. To decrease calculation times for the bike seat, the resolution was reduced from 0.1 mm to 0.5 mm. This change was made because the calculation times for the lattice structures with 0.1 mm resolution would be 20 times longer than those with 0.5 mm resolution.