## 4 Results
### Session/Period-Based Analysis
The designer presents higher shares of non-geometrical modeling in the initial sessions (\(\sim\)20%), when families were being defined, and a higher share of geometrical modeling for the rest of the experiment (\(\sim\)30%), which are considered normal behaviors for this specialist. In addition, it was expected that the structural designer would demonstrate a more constant share of collaborative commands than he in fact did (\(\sim\)5%), since clashes are common between this and the other disciplines' models. Figure 7: Share of commands by sub-category and time period for each designer. The timeline for the mechanical designer shows at least three entire sessions without participation (periods 16-20 and 65-74), and several long pauses (periods 1-2, 9-10, 27-28, 35, 86, and 90). This non-contributory behavior is to be expected at the initial stages of the project since MEP specialists are waiting for the architect and structural engineer to provide the basic elements of the building in order to model the installations. However, the initial stages should be dedicated to defining the necessary families for the project, and in more advanced stages a better planning of workflows should provide the various specialists with tasks that ensure constant contribution to the project. It can also be observed that the necessary commands executed by the mechanical designer (\(\sim\)40%) approximately doubled the amount of contributory commands (\(\sim\)20%), which could indicate that this specialist used an excessive number of auxiliary commands, such as hiding elements or modifying visualization options. This kind of modeling practices require a more detailed analysis of the command patterns executed in order to increase the designer's performance by providing personalized training. The electrical specialist did not participate in two entire sessions (periods 11-20) and took several long pauses throughout the experiment (periods 21, 26, 41-42, 56, 59-60, and 76). A significant share of backwards commands can be identified in the first half of the timeline (\(\sim\)20-40%), which decreases in the second half (\(\sim\)5-15%). This may indicate an improvement in the modeling skills of this designer. Again, his share of necessary commands (\(\sim\)40-50%) is virtually double that of contributory commands (\(\sim\)20-25%), while a nearly constant share of collaborative commands is evident (\(\sim\)3%), through which this specialist received updates from the rest of the designers. Finally, the plumbing designer shows a large constant share of backwards commands (\(\sim\)20-40%), but the lowest share of unnecessary commands (\(\sim\)10%). Additionally, a high proportion of necessary commands with respect to contributory commands is apparent (\(\sim\)40-50% to \(\sim\)20-25%), as well as a high provision of non-geometrical information to the model (\(\sim\)10%) and a variable share of collaborative commands (\(\sim\)5-30%). According to this analysis, it would be advisable to train the architectural designer in order to reduce the use of unnecessary 'Cancels', which apparently this specialist does while thinking. The structural, mechanical and plumbing designers' training should focus on reducing the number of backwards commands, for which a deeper analysis of the specific causes should be performed previously. This analysis should be based on detecting bad practices through the study of command patterns. All the MEP designers should receive training in order to reduce the quantity of necessary commands that they execute to produce a more effective modeling process, since necessary commands do not really contribute to the model but are only auxiliary commands that sometimes can be avoided through good modeling practices. While the plumbing specialist's command intensity and distribution was more constant than that of the other MEP designers, the analysis indicates that this designer needs further training in BIM modeling in order to avoid using that significant share of backwards commands.