# Analysis of Planar Double-Layer Timber Spatial Frames by Using Parametric Tools
## 4 Conclusions  
### Topologies  
One of the objectives of the paper is to define the scope of each of the seven topologies, their strengths and limitations. After analyzing the results, the following conclusions are drawn:  
* Group A (A1-A2-A3): These are the most balanced topologies, applicable in various situations. In this regard, it is only logical that they are the most common ones used. Of the three, A1 is the worst performer; its cubic module means that with the greatest number of nodes per square meter, it still has the greatest deformation.
* On the other hand, the semi-octahedral modulus provides A2 and A3 meshes with sufficient stiffness without affecting the mass too much. Between the last two, there is not that much difference; A3 turns out to be a good alternative to A2 when mass/economics is the determining factor, without serious detriment in deformations. In general, all three are relatively simple geometry topologies and easy to fit.
* Group D (D1-D2): their tetrahedral modulus makes them extremely rigid. Especially D1 is the preferred choice for large spans (over 40-50 m). From these spans on, the mesh starts to be competitive: the node-bar/m\({}^{2}\) ratio decreases drastically (which makes them more cost-effective) and the depletion rates go up (which indicates that the structure is working). A future research task would be to further analyze the limits of tetrahedral meshes in larger spans (above 50 m).
* The D2 mesh is presented as a good alternative to D1. Although the lower layer detaches a significant number of bars to form hexagons, it is still a rigid mesh, competitive for its lightness (with deformations lower than those of mesh A3, also lightened). One drawback that can arise is the difficulty in handling the hexagonal geometry. If the project does not contemplate the use of these characteristic shapes from the beginning, edges and joints can become an added complication.
* B1: It can be a good alternative to A2 mesh. The metrics (number of bars and nodes) are better, and for what is saved in elements, the deformations do not increase so much.
* The only doubt that may come up is (as in the D2) the geometry itself. As the bars are not arranged parallel to the edges, bars of special lengths arise to finish off the mesh, problems that group A can avoid.
* C1: Of the seven topologies, C1 is the one that behaves the worst in general. It tends to destabilize easily, and it is comfortable up to a 20-25 m span. Beyond this limit,it becomes very limited. It is also the topology that needs more nodes and bars per square meter (slightly more than D1). In general, it seems that the geometry is not appropriate for generating a structural space frame.  
It should be mentioned that in order to analyze the behavior of the topologies, the structure has been pushed to the limit. Some of the results collected in this paper, although complying with the standards, are quite tight (the deflections of the supports on three sides and the depletion indices). In the development of the calculation, the results should be handled more loosely, although for the purpose of this academic work, they are the appropriate ones.  
Although the scope of the work has been flat meshes, the application of the system could be extrapolated from the plane to the curved surface and analyze, for instance, cylindrical or spherical meshes. This is a field to be explored in future projects.